Rubio outlined in April 2015 a proposed individual tax reform plan that would have only two rates, 15 and 35 percent, in exchange for eliminating many deductions and exemptions. Deductions for charitable contributions and mortgage interest would remain. He later revised his plan in October 2015 to include a 25 percent tax bracket. For businesses, Rubio would have a 25 percent tax rate and allow immediate expensing of capital investments. Capital gains and dividend income would be tax-free.

In September 2015, Rubio proposed federal tax credits to employers who provide paid medical and maternity or paternity leave, up to $4,000 per employee. He has also called for reducing the federal gas tax by 80 percent, instead giving states greater authority over transportation spending (and presumably raising their own gas taxes).

In the past Rubio has advocated for making the Bush tax cuts permanent, cutting the corporate tax rate in exchange for eliminating deductions and exemptions, and an overall lower level of taxation that will help the economy to grow. Along with Coons of Delaware, he has taken the lead in extending various business-friendly tax provisions that generally are set to expire on an annual basis. While these tax provisions, which include breaks for research and development as well as capital investment, can be seen as maintaining the complexity and favoritism embedded in the current tax code and therefore at odds with free-market thinking, without these extensions the overall level of taxation would increase and further stunt an already lagging economy.

He voted against the “fiscal cliff” deal at the end of 2012 that renewed most of the 2002 Bush tax cuts but increased taxes on higher-income earners.

Rubio has been a staunch advocate of cutting federal spending. Among other proposals, he has called for spending on non-defense programs to be frozen at 2008 levels, and he supports a balanced budget amendment. He has submitted legislation to return approximately $45 billion in federal funds sitting unused in accounts, as well as to eliminate earmarks.

Rubio has also supported legislation to reduce the federal workforce by 10 percent over four years through attrition. According to an analysis by the National Taxpayers Union Foundation, Rubio has introduced legislation that would, if enacted, total a $330 billion annual cut in federal spending.

Rubio opposed the Paul Ryan budget in 2011 that raised spending in the short term in exchange for promised spending cuts in 2022 and 2023, arguing that it added $60 billion in spending in the short term that was likely to wind up being continued instead of eliminated over time. In 2011, Rubio voted against the budget deal that included sequestration, citing its failure to deal with the long-term debt problem, avoid potential credit downgrades, and didn’t shrink government or address health care costs.

Rubio has announced his opposition to the October 2015 budget and debt-limit deal that raises spending caps in exchange for future budget cuts.

He has proposed repealing Davis-Bacon, a Depression-era law that requires contractors on building projects using federal funds to pay union-scale wages, which are typically higher than the market rate.

Rubio has released his own plan for replacing Obamacare and reforming health care. The plan centers on refundable tax credits available to all Americans to purchase insurance, establishment of federally funded high-risk pools for those with pre-existing conditions, and expanded use of Health Savings Accounts. He would also transition Medicare to a premium-support plan.

Rubio campaigned against Obamacare in his 2010 election, and has been a reliable vote for repealing it. Rubio has spoken in favor of block granting Medicaid to the states, along with other means-tested welfare programs.

Rubio unveiled the “Rubio Doctrine” in May 2015, anchored on three tenets. First, a strong military, which requires undoing the sequester budget cuts to defense spending. Second, the U.S. military and diplomacy should be used to defend U.S. economic interests, such as protecting shipping lanes and opposing economic disruption caused by one nation’s invasion of another. Third, he called for “[m]oral clarity regarding America’s core values” and said, “We must recognize that our nation is a global leader not just because it has superior arms, but because it has superior aims.”

In his nearly four years in the Senate, Rubio has staked out a number of positions that suggest he tends towards the more-hawkish wing of the Republican Party, such as favoring keeping military options on the table in Iran and Syria. He has supported keeping sanctions on Iran and strengthening them until the country abandons its nuclear weapons program, and also urged the Obama administration to relist North Korea as a state-sponsor of terrorism because of that nation’s support for Iran and Syria.

In March 2015 Rubio was among a group of 47 Republican senators who signed an open letter to the Iranian regime explaining any deal negotiated between the Obama administration and Tehran that was not approved by Congress could be undone by executive action of the next president. He also said the U.S. should have insisted Iran give up its ballistic missile program as part of any deal and that if elected president he would reimpose sanctions on Iran.

Rubio favored arming moderate Syrian rebels at the beginning of the struggle against Assad and expressed concern early on that Libya would become a safe haven for terrorists after the fall of Gadhafi, where he argued the U.S. should have engaged “fully and decisively.” On Iraq, he has said that based on what is now known about Iraq’s lack of weapons of mass destruction, he would not have supported the invasion. He would provide greater support to Saudi Arabia in its fight against extremists and rebels in Yemen, including putting U.S. special operations forces on the ground. He has also said he would consider putting U.S. troops on the ground in Iraq to combat ISIS.

Rubio originally said he was open to accepting large numbers of Syrian refugees, but he expressed concern about ensuring terrorists were effectively screened out. Following the November 2015 attacks in Paris in which at least one of the ISIS terrorists had come to France as a refugee, he said there was no satisfactory way to vet all of the refugees and he would oppose bringing any of them to the U.S.

Rubio favors a “two state solution” regarding Israel and the Palestinians, but has said the conditions don’t currently exist to allow that, specifically citing the lack of “responsible leadership” in the Palestinian government.

He harshly criticized the Obama administration’s decision to begin normalizing ties with Cuba. Addressing the issue in May 2015, Rubio said that as president, “I would reimpose sanctions that could only be lifted through reciprocal steps on behalf of the Cubans. In essence, if they want more telecommunications opening, then the Cuban government will have to allow freedom of the press. If they want more engagement with American business and travel, then they will have to allow more democratic opening for alternative groups in society.”

On Ukraine, Rubio has favored stiffening sanctions against Russia and helping Ukraine to stabilize its economy through a currency board that would set a fixed convertibility rate to either the euro or the dollar. He is a co-sponsor of legislation authorizing the president to provide weaponry to Ukraine to allow it to defend itself against Russia, and has described Russian President Vladimir Putin’s main goal as rebuilding his country into a major geopolitical force. Rubio favors additional sanctions preventing state-owned firms from doing business in the West as well as positioning more NATO troops in the Baltic nations.

He criticized China’s building of islands with military airstrips in international waters, calling them “illegitimate” and saying he supported having U.S. Navy ships transit the areas to affirm they are international waters. He has also said the U.S. should respond in kind to cyberattacks, pointing to the apparent hacking of the Office of Personnel Management’s computers by the Chinese, but urged caution regarding Chinese currency manipulation charges saying the U.S. shouldn’t start a “currency war” with China.

Rubio also called for the U.S. to strengthen its ties with Taiwan, including stepping up sales of military equipment and bringing it into international trade organizations.

He signed a letter urging defense cuts required under sequestration be replaced with cuts elsewhere, and wrote in a March 2015 op-ed that “our highest priority during the ongoing budget debate should be undoing the damage caused by defense sequestration and the hundreds of billions of dollars of defense cuts made by the Obama administration.”

He has supported extending the wiretap provisions of the Patriot Act and also keeping Guantanamo open as a prison for terrorists and enemy combatants. He also has referred to Edward Snowden, a former NSA contractor who stole classified information about American surveillance programs before fleeing to China and then Russia, as a “traitor.”

Rubio serves on the Foreign Relations Committee and is the ranking member of the subcommittee handling East Asian and Pacific affairs, and he sits on the Select Committee on Intelligence.

In 2015 Rubio spoke primarily about American exceptionalism during a speech to the Conservative Political Action Conference, saying, “For over two centuries we’ve been an exceptional nation, a place founded on the belief that every man, woman, and child was born with a God-given right to life, and liberty, and to pursue happiness.… Americans know we’re exceptional. And you know who else knows we’re exceptional? The world does. After all, when was the last time you heard about a boatload of American refugees arriving on the shores of another country?”

Rubio has pledged that if elected president, he would “nominate judges and justices committed to applying the Constitution as written and originally understood.” He has called the Roe v. Wade decision “egregiously flawed”  and “blatant judicial activism.”

Rubio said that he “disagreed” with the Supreme Court’s decision in King v. Burwell (Obamacare tax credits), saying they “once again erred in trying to correct the mistakes made by President Obama and Congress.” Rubio also said that he “disagreed” with the court’s decision in Obergefell v. Hodges, but also stressed that “we live in a republic and must abide by the law.” He called the Citizens United v. FEC decision “victory for those who truly value the freedoms outlined in our First Amendment.”

In 2013 Rubio proposed what was described as “the most far-reaching school choice legislation in U.S. history,” a plan that would allow low-income parents to use vouchers from private organizations that receive funding through a new federal tax credit available to both individuals and corporations. The proposal is in line with Rubio’s long-standing support of school choice, going back to his advocacy for Florida’s voucher program that relies on a similar funding mechanism.

Rubio also signed on as a co-sponsor of legislation that would convert up to $14 billion in federal Title I school aid to be converted to school vouchers for low-income students and has expressed his opposition to the federal Common Core standards.

On higher education issues, Rubio has proposed creation of a new accreditation process that would allow new, low-cost providers of college education to offer their services to students. He also favors developing a progressive payment process for student loans that would tie repayment to income.

On First Amendment issues Rubio voted against the DISCLOSE Act, which would restrict political speech and expose people who donate to independent advocacy groups to harassment and retaliation.

He also supported the Supreme Court’s decision in the Hobby Lobby case, favoring religious liberty against government mandates, and introduced legislation amending the Religious Freedom Restoration Act to specifically protect employers who do not want to be forced to provide contraceptive coverage under Obamacare. In the case of a Kentucky county clerk refusing to issue marriage licenses in response to the Supreme Court’s same-sex marriage ruling, he has said the clerk’s office should issue licenses but the clerk’s religious objections should be protected as well.

Rubio supported an Arizona immigration law based on 10th Amendment principles, and as a candidate in 2009 he expressed strong support for the 10th Amendment. He is the co-sponsor of a federal ban on Internet gambling, something a New York Times article noted puts Rubio “at odds with movement conservatives (i.e. federalists) who believe that, under the Constitution, states should have the right to decide for themselves whether to legalize online gaming.”

In a February 2016 campaign trip to Nevada, a state where prostitution is legal, Rubio said while he thinks prostitution should be illegal, he would not favor a federal law prohibiting it, saying it should be up to the voters of Nevada to decide.

Rubio has consistently supported individual gun rights, and recently received an A grade from the National Rifle Association after introducing legislation rolling back gun control laws in Washington D.C.  Prior to that, he had a B+ from the group, largely based on his record in the Florida legislature. As speaker of the House he helped push through the state’s “Stand Your Ground” legislation that protects an individual’s right to use a gun in self-defense instead having to retreat, but it was seen as not sufficiently supportive of a bill allowing employees to bring firearms onto their employers’ property. Following the December 2012 shooting at Sandy Hook elementary school, he criticized Obama’s gun control proposals and said the focus should be on keeping guns out of the hands of criminals and the mentally ill. He also said he opposes barring people on federal government watch lists from purchasing guns, citing the large number of people on the lists with no connection to terrorism.

Rubio is pro-life and believes abortion should only be legal in cases where the life of the mother is jeopardized. He has supported legislation in the past that includes such exceptions however. He was a sponsor of the Child Interstate Abortion Notification Act that would have prohibited taking a minor to another state for an abortion in order to evade state parental consent or notification laws, and also require abortion providers notify parents in the case of an out-of-state minor seeking an abortion. The legislation did not pass.

Rubio has said he believes marriage is only between a man and a woman, and that he opposes the Supreme Court’s decision on the issue. He has also said he opposes a constitutional amendment overturning the court’s ruling, saying that it should be left up to each state to determine its own marriage laws.

Rubio has been a reliable ally of conservative causes.

An early example of Rubio’s efforts to keep campaign promises was a book he created as speaker of the Florida House, 100 Innovative Ideas For Florida’s Future, that outlined a legislative agenda he pledged to pursue. The promises included a better website for the state’s budget, bringing Hollywood productions to Florida, and reducing taxes and property insurance premiums.

According to Rubio, all 100 measures were passed by the Florida House, with 57 of them passing the Senate and being enacted into law. Although that claim requires some generous accounting of what passed and in what form, it’s clear that Rubio did all that might be expected to get legislation passed reflecting the agenda outlined in 100 Innovative Ideas For Florida’s Future.

As a U.S. senator, Rubio has consistently upheld his pledges to oppose tax increases and oppose climate change regulations, and he otherwise voted largely in line with the conservative, limited-government perspective he shared as a candidate – except on immigration.

As a candidate, Rubio announced that he opposed “amnesty,” which he said included anything that allowed those in the U.S. illegally to remain and have the opportunity to become citizens. As a senator, however, Rubio helped to craft the so-called “Gang of Eight” immigration reform package that allows currently illegal immigrants to remain in the U.S. and gain legal status, and eventually have an opportunity to become citizens.

He has since backed off of his support for a comprehensive bill, arguing instead that a piecemeal approach should be taken, with border-enforcement measures coming first.

Some have suggested he embellished his parents’ story of emigrating from Cuba to the U.S. as political refugees, given that they arrived in the U.S. before Castro took power. Rubio has explained the discrepancy as based on his recollections as a child of his parents’ explanation of how they came to the U.S., and has since corrected the record.

As speaker of the Florida House, Rubio was given a credit card by the state Republican Party for political expenses as he worked to help promote Republican candidates. Some of the charges on the card were for personal expenses, which Rubio said were authorized by the party so long as he reimbursed the party for those expenses

In Rubio’s personal life, there is little hint of scandal, unethical behavior, or other indicators suggesting significant moral lapses.

Rubio’s history demonstrates a long-term commitment to the conservative principles he espouses and that guide him.

Rubio has regularly promoted conservative ideas. His proposal to eliminate property taxes in Florida in exchange for a hike in the sales tax gained him national attention, and while perhaps neither conservative or liberal, it does suggest a willingness to think outside the box and promote bold reforms.

In January 2014 Rubio proposed eliminating the Earned Income Tax Credit (EITC) and replacing it with a low-wage subsidy. The EITC has been widely criticized by many conservatives for its high degree of fraud and abuse.  He also co-authored an op-ed with Sen. Mike Lee of Utah advocating for fundamental reform of the personal tax code, arguing for a simpler system with two rates of 15 percent and 35 percent with the elimination of many deductions and credits.

Rubio has also not hesitated to challenge liberal positions and officeholders. In February 2014, Democratic Sen. Tom Harkin returned from a trip to Cuba and extolled the virtues of the communist country’s health care system. Rubio promptly launched a blistering rebuttal of Harkin’s comments, describing the numerous repressive policies Cuba has toward dissidents as well as the Castro regime’s untrustworthiness regarding the quality of health care provided in the communist dictatorship.

His committee assignments include Commerce and Foreign Relations, generally considered to be among the higher-prestige committees, suggesting he enjoys the confidence of his colleagues in terms of his knowledge and seriousness.

Rubio’s most significant coalition-building accomplishment to date was the introduction and passage in the U.S. Senate of the “Gang of Eight” immigration reform bill. While widely criticized by many conservatives, his work on immigration does show a willingness and ability to work with political opposites to achieve consensus. Rubio has also worked with Democratic Sen. Coons of Delaware to extend many business tax breaks and expand legal immigration for high-skill workers, measures that generally enjoy broad support in both parties.

The book he wrote as speaker of the Florida House, 100 Innovative Ideas For Florida’s Future, outlined a legislative agenda he pledged to pursue. The promises included a better website for the state’s budget, bringing Hollywood productions to Florida, and reducing taxes and property insurance premiums.

According to Rubio, all 100 measures were passed by the Florida House, with 57 of them passing the Senate and being enacted into law. Although that claim requires some generous accounting of what passed and in what form, it’s clear that Rubio did all that might be expected to get legislation passed reflecting the agenda outlined in 100 Innovative Ideas For Florida’s Future.

Rubio was selected by his fellow Republicans in the Florida State House to serve as party whip, majority leader, and then speaker of the House, which also demonstrates significant political savvy and the ability to work with and gain the respect of his colleagues, not to mention ambition. As party whip, he preferred persuasion over arm-twisting, according to colleagues, and once in the speaker’s office, he delegated and decentralized power by giving more authority to committee chairs.

He also possesses considerable political skills, as his come-from-behind win in the 2010 nomination fight with Crist demonstrated. He performed well in debates, and showed a good grasp of the facts regarding policies and issues.

In January 2014 Rubio proposed eliminating the Earned Income Tax Credit (EITC) and replacing it with a low-wage subsidy. The EITC has been widely criticized by many conservatives for its high degree of fraud and abuse.  He also co-authored an op-ed with Sen. Mike Lee of Utah advocating for fundamental reform of the personal tax code, arguing for a simpler system with two rates of 15 percent and 35 percent with the elimination of many deductions and credits.

Rubio is widely regarded as an effective communicator, one of the reasons he was selected to introduce Mitt Romney at the 2012 Republican National Convention and to give the Republican response to Obama’s State of the Union speech in 2013. His introduction of Romney was termed “captivating” by The Washington Post, and his State of the Union speech was generally well regarded although he was criticized for taking a drink of water halfway through.

During the two years before being elected speaker of the House, Rubio traveled Florida holding what he called “idea raisers,” where he solicited citizens’ input on policies and legislation that would improve the state. Many of the ideas from the events became the basis for his 100 Ideas book, and his statewide tour was hailed as “a work of genius” by former U.S. Speaker of the House Newt Gingrich.

The single biggest vulnerability that Rubio would face in a presidential nomination contest is both his position and history of flip-flops on the immigration issue. Opponents of amnesty, however that term is defined, are likely to be unhappy with his support for the Gang of Eight comprehensive reform bill that would allow most illegal immigrants to remain in the U.S. with a pathway to citizenship. Even some who support his position may be troubled by his original opposition to such a policy while campaigning in 2010, his later support of it, and then his backing away from the legislation after encountering fierce opposition from many conservatives.

Rubio has missed nearly a third of U.S. Senate votes between January and October of 2015. He has defended his record, saying voting is only a small part of his job as a senator, but it is likely to be an issue in his pursuit of the GOP nomination and the general election if he is the Republican candidate.

Rubio’s co-ownership of a Florida house with longtime friend and fellow state legislator David Rivera will be a problem. The house began foreclosure proceedings in 2010, although Rubio and Rivera quickly brought the mortgage current. More problematic for Rubio, Rivera is currently under investigation for serious campaign finance and political corruption charges. The house was finally sold in early June of 2015.

Rubio’s use of a credit card provided by the Republican Party of Florida for personal expenses is also likely to be brought up by opponents.

Finally, Rubio’s youth and relative inexperience could be liabilities on the campaign trail. Although he held positions of leadership in the Florida State House, the fact remains he is still a first-term U.S. senator without a substantial track record on the national stage.

Marco Rubio receives high marks for issues and character and a lower mark for consistency.

Rubio consistently scores high in all areas but recently has demonstrated consistency problems on immigration and sugar subsidies. Although youthful in appearance, he has political experience that belies his youth in state and federal offices. His public demeanor is principled but not divisive and cautiously hopeful without an appearance of gloom.

Rubio continues in the upper ranks of fundraisers and his viability seems to be gaining momentum. A central concern for many people is that his youthful appearance projects a sense of inexperience. In contrast, his strong debate performances and his command of the issues – in addition to his serious legislative experience in state and federal service – should overcome concerns about his perceived youth.