Marco Rubio, then the junior United States senator from Florida, formally announced his 2016 presidential campaign on April 13, 2015, at the Freedom Tower in Downtown Miami.Jaffe, Alexandra; Bash, Dana (April 13, 2015) "He's in: Marco Rubio announces presidential bid", CNN. Retrieved April 14, 2015. Early polling showed Rubio, who was considered a potential candidate for vice president by Republican presidential nominee Mitt Romney in 2012, as a frontrunner candidate for the Republican nomination for president of the United States in 2016 since at least the end of the 2012 election.Nelson, Rebecca (April 13, 2015) "Marco Rubio Makes His Pitch as the Fresh Face of the GOP in 2016", National Journal. Retrieved April 14, 2015. Rubio was the second Cuban American to run for president, with Republican Ted Cruz announcing his campaign three weeks earlier. He suspended his campaign on March 15, 2016, after finishing second in Florida's primary.

Later that year, the Republican nominee, Donald Trump, was elected president in the presidential election. Eight years later, after Trump's re-election to a non-consecutive term, he nominated Rubio as Secretary of State.

Background

2012 presidential election

As early as January 2011, there had been speculation that he might seek the office of the president or vice-president. In January 2011, Rubio stated he had no interest in being the vice-presidential candidate in the 2012 presidential election. Despite his comments, speculation continued that presidential candidate Mitt Romney might select Rubio as his running mate. According to the book Double Down, Romney's campaign narrowed down his list of potential nominees for vice president to five candidates, one of which was Rubio. However, Romney ultimately picked Wisconsin congressman Paul Ryan.

2016 presidential election Throughout 2014, groups had been raising money to support a potential Rubio presidential campaign. Groups supporting Rubio raised over $530,000 in the first three months of 2014, most of which was spent on consultants and data analytics, in what was seen as preparations for a presidential campaign.

Early polling data showed Rubio as a frontrunner for the nomination shortly after the 2012 election. From late 2012 to mid-2013, Rubio came in first in eight consecutive national polls among potential 2016 candidates, from such sources as Public Policy Polling, Harper Polling, Quinnipiac University, and Fairleigh Dickinson University. In statewide polls, he had performed most prominently in his home state of Florida, alongside Jeb Bush, and has also performed fairly well in Suffolk University polls in such states as Colorado, Michigan, and Minnesota. A poll from the WMUR/University, tracking New Hampshire Republican primary voters' sentiment, showed Rubio at the top alongside Kentucky senator Rand Paul in March 2013. However, he had dropped to 10th place behind other Republican contenders by April 2014. The poll, however, also suggested that Rubio was not disliked by primary voters, which could have been positive for him had other candidates chosen not to run. By the time of Rubio's announcement, he had regained some standing in the polls. A March 2015 NBC/Wall Street Journal poll asked Republican Party voters if they could see themselves supporting the various candidates. Rubio won the poll with 56 percent of Republican voters saying they could see themselves supporting Rubio, while only 26 percent said they could not. Wisconsin governor Scott Walker and former Arkansas governor Mike Huckabee trailed just behind Rubio with 53 and 52 percent, respectively. A CNN/ORC poll conducted from March 13 to March 15, 2015, found that Rubio was tied with Chris Christie for the Republican nomination.

In January 2015, Rubio began laying the foundation for a presidential campaign. He began contacting top donors and appointed advisors, including George Seay, who previously worked on Rick Perry's 2012 presidential campaign and Mitt Romney's 2008 presidential campaign, and Jim Rubright, who had previously worked for Jeb Bush, Romney, and John McCain. Rubio also instructed his aides to "prepare for a presidential campaign" prior to a Team Marco 2016 fundraising meeting in South Beach.

Campaign

On March 30, 2015, Rubio announced on Fox News and through social media that he would be making a "big announcement" on April 13 in Miami, Florida. While he did not specify whether the announcement pertained to his reelection as a U.S. senator or for the Presidency, most media consensus was that Rubio would be announcing his presidential run. He made the announcement at the Freedom Tower in Downtown Miami. In his announcement speech, Rubio cast himself as forward-looking and a leader for a new generation of Americans, in contrast to Democrat Hillary Clinton, who announced her presidential campaign the day before; in addition, he announced he would not seek re-election as senator. With the announcement, Rubio became the fourth major candidate to officially announce a run after Republicans (and fellow senators) Ted Cruz of Texas and Rand Paul of Kentucky and Democrat Hillary Clinton.

Although Rubio initially struggled to poll as well as other frontrunners such as Chris Christie, Jeb Bush, Scott Walker, and Donald Trump, Rubio's performance in the debates was widely seen as a boosting factor in his rising poll numbers in the late summer and fall of 2015. Over the course of both of the first two debates, in August and September, Rubio was widely praised as one of the top performers, even being called the winner by some analysts. As a result, Rubio's poll numbers began to increase once more, and he eventually reached the #3 position in most polling averages, only behind Trump and Ben Carson. Another factor that was seen as greatly improving Rubio's chances was the exit from the race of Scott Walker on September 21. Analysts claimed that many of Walker's supporters and donors were turning to him as a viable alternative to Bush, who could also claim broad appeal to both moderates and conservatives. With Walker out of the race, Rubio was widely viewed as the next likeliest candidate who best matched this criterion. The Rubio campaign was even reported as hiring up to nine of Walker's former top staffers less than 24 hours after his exit.

Matt Lewis has commented that, "Democrats should fear Marco Rubio", who Lewis saw as "heralding a generational shift" for Republicans.Matt K. Lewis - "Geriatric Democrats should fear Marco Rubio and the Republican youth wing; Florida Senator's debate triumph comes as Paul Ryan is elected Speaker, heralding a generational shift that conservaties must seize", The Telegraph, October 31, 2015. Retrieved 2015-11-02 Rubio, along with Paul Ryan and his recent ascension to the House speakership, Lewis says, means "both men will be attacked for their youth and energy", adding: "But it's hard to look at this strong and diverse Republican bench, and not juxtapose it to the Democrats, whose party – now that Barack Obama is a lame duck – seems to be represented by a bunch of old white people, such as Hillary Clinton, 68, Bernie Sanders, the 74-year-old democratic socialist candidate, ...Nancy Pelosi, 75, and Harry Reid, 75... For Democrats, who were hoping they would get to deal with old pols like John Boehner and Jeb Bush...the world just got a little bit scarier".

The November 2015 Paris attacks were widely seen as altering the narrative of the 2016 presidential primaries, and in particular gave a boost to Rubio for his foreign policy stances, in comparison to such candidates who were softer on foreign policy such as Carson, and also for his having political experience, in contrast to other front-runners such as Trump.

During the latter part of 2015, Rubio's voting record in the senate came under scrutiny. Jeb Bush, during the CNBC debate on October 28, told Rubio that he could either campaign or resign, Rubio responding that Bush had not made similar comments about the voting record of John McCain during his 2008 presidential campaign and concluded that Bush was only criticizing "because we're running for the same position and someone has convinced you that attacking me is going to help you." In December, while in Iowa, fellow presidential candidate Chris Christie mentioned Rubio missing a vote on a national spending bill the senator opposed and added, "Just show up to work and vote no, and like if you don't want to, then quit." On December 29, Rubio responded to Christie by claiming to have close to a 90% attendance record while also retorting that the governor had "been missing in New Jersey half of the time." In late December, Right to Rise, a Jeb Bush super PAC, released an ad claiming that Rubio had both missed a classified meeting the previous month after the Paris attacks and "missed more total votes than any other senator". On January 7, Rubio defended his record by arguing that votes were "precooked" and votes were used to "make a statement."

Rubio participated in the January 28 Fox News debate, charging Cruz with building his campaign on "the lie" stemming from his stance on immigration and insisting in Jeb Bush's book Immigration Wars: Forging an American Solution that the latter changed his "position on immigration". January 29, during an interview the following day, Rubio was confident about his chances in Iowa, though did not deny that Ted Cruz was the frontrunner since by Rubio's admission, "He's spent basically all of his money in Iowa."

Early primaries Rubio finished in third place in the Iowa caucus on February 1. Though polling had shown him in third place prior to the caucus, the result was still treated as a surprisingly strong showing. Amber Phillips of The Washington Post wrote of Rubio's performance, "He over-performed expectations, and for that, Rubio perhaps almost as much as Cruz can call Monday a win." After being projected in third place, Rubio said in a speech that he had defied expectations and swore that when he was the nominee of the election cycle, "we are going to unify this party, and we are going to unify the conservative movement". A little over a week after the primary, on February 10, Rubio accused Cruz of having misled voters through claiming fellow candidate Ben Carson would be ending his campaign in what he called "a concerted effort that I'm sure they planned to execute on something in order to influence the election."

Going into New Hampshire, Rubio by February 5, four days after the Iowa victory, was polling at an average of 16%. This placed him in second place, behind Trump. At the New Hampshire debate on February 6, 2016, Rubio was criticized by Christie for repeating memorized speeches, to which Rubio replied by repeating four times a statement to the effect that President Obama was destroying America. Rubio defended these remarks the following day, saying with respect to the statement that Obama "knows exactly what he's doing" that "It's what I believe and it's what I'm going to continue to say, because it happens to be one of the main reasons why I am running." Rubio came in fifth place during the New Hampshire primary on February 9. Shortly afterward, Rubio admitted to supporters that he was disappointed and concluded that his debate performance three days prior had not helped him in the state. Chris Christie, who came in sixth place behind Rubio, dropped out the following day. Rubio responded to his ended candidacy by praising him.