Ledyard King

USA TODAY

Sen. Marco Rubio ended his presidential bid Tuesday after losing the Republican primary in his home state of Florida, the low point in a season of ups and downs for the first-term senator.

Rubio told supporters that while his campaign may have been on "the right side," in 2016 it would not be on "the winning side."

The results in Florida almost mirrored pre-primary polls showing Donald Trump leading Rubio by 20 points. Sen. Ted Cruz of Texas finished third and Ohio Gov. John Kasich finished fourth.

In a nearly 15-minute concession speech at Florida International University in Miami, Rubio tried to sound upbeat.

"While it is not God's plan that I be president in 2016 or maybe ever ... the fact that I've even come this far is evidence of how special America truly is," he told a cheering crowd, some of whom shouted pleas for him to stay in the race.

Rubio won only three nominating contests — in Minnesota, Puerto Rico and the District of Columbia. He was far behind second-place Texas Sen. Ted Cruz and Trump in the race for delegates.

Initially, Rubio had aspired to emerge as the top candidate of the GOP establishment in a one-on-one race against Trump. But a steady stream of third- and fourth-place finishes forced him to change his game plan. Toward the end, his hope was that Trump would fall short of the 1,237 delegates needed to win the nomination, and that Rubio himself would somehow claim victory at a contested convention.

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"While this may not have been the year for a hopeful and optimistic message about our future, I still remain hopeful and optimistic about America," he told supporters Tuesday night.

Now that his White House bid is over, Rubio, whose Senate term expires in January, has several options to move forward with his political career.

He can refile to run for re-election to the Senate this fall, but he dismissed that possibility while running for president, citing his frustration with the slow pace of Congress. He also could also lay the groundwork to run for Florida governor in 2018, when Republican incumbent Rick Scott must give up the office due to term limits.

There's also the remote possibility Rubio be chosen as a running mate by the eventual GOP presidential nominee, though that seems highly unlikely if Trump wins the nomination, given their feuding in recent weeks.

Ohio Gov. John Kasich, the only establishment-backed candidate left in the race after wining his home state, tweeted his assessment that Rubio will continue to be a force in the Republican Party.

In his concession speech Tuesday, Rubio indicated that Trump's ascension was years in the making and had its roots in the Great Recession.

"We worked as hard as we ever could," he said. "American’s in the middle of a real political storm, a real tsunami and we should have seen this coming. People are angry and people are very frustrated about the direction of our country. There’s millions of people in this country that are tired of being looked down upon, tired of being told by these self-proclaimed elitists that they don’t know what they’re talking about and they need to instead listen to the so-called smart people."

When he entered the race on April 13 last year, Rubio, a 44-year-old Cuban American, heralded “a new American century, offered youth, optimism and a chance for the GOP to connect with Hispanics. But his platform — a muscular foreign policy, calls for smaller government and strong family values — spoke to traditional conservative principles.

And while he called for passing power to a younger generation, his opposition to gay rights, cautious approach to climate change and hard line against thawing relations with Cuba seemed out of step with many millennials.

Expectations were that he would be overshadowed in the Republican nomination race by former Florida governor Jeb Bush, the GOP's establishment's clear favorite and Rubio's mentor when the senator was speaker of the Florida House.

But Rubio proved to be a better campaigner than Bush, who had trouble distancing himself from the legacy of his brother, former president George W. Bush, and became an easy target for Trump. With strong debate performances and stumbles by others in the crowded GOP field, Rubio rose slowly in the polls, despite questions about his relative lack of experience.

Rubio's surprisingly strong third-place finish in Iowa's Feb. 1 caucus boded well for his goal of becoming the top choice for a GOP establishment looking for an alternative to Trump and Cruz.

But cracks appeared ahead of the New Hampshire primary when New Jersey Gov. Chris Christie ridiculed Rubio at a debate for repeating the same scripted attack on President Obama several times in the space of five minutes.

“There it is, the memorized 25-second speech,” Christie said, looking out at the audience.

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The exchange reinforced doubts about whether Rubio, elected to the Senate in 2010 on a wave of Tea Party support, was ready to be president. He also was hampered by his record of missing Senate votes to campaign, his initial support in 2013 for immigration legislation that would have provided a pathway to citizenship for people in the country illegally, and his misuse of a Florida GOP credit card when he served in the state legislature.

Rubio finished fifth in New Hampshire but rebounded in South Carolina on Feb. 20, finishing second with the help of key endorsements. Bush dropped out of the race that night, but that wasn't enough to give Rubio an outright win three days later in Nevada. He finished in second place, a disappointing 22 points behind Trump.

With his campaign unraveling, Rubio decided he had nothing to lose by adopting Trump's strategy of personal attack. Ahead of the March 1 Super Tuesday primaries, he hurled insults at the real estate tycoon, slamming him for using spray tans that turned him orange and accusing him of having small hands.

“And you know what they say about men with small hands,” Rubio said, pausing for dramatic effect. “You can’t trust them.”

The move seemed to backfire. Rubio won just one Super Tuesday state — Minnesota — and did no better than third in most of the others. He later said he regretted his attacks on Trump, but the damage had been done.