Sen. Marco Rubio (R-Fla.) has ended his campaign for president.

The senator, once hailed as the "Republican savior " for his initial efforts to broaden the GOP to immigrants and young people, suffered an embarrassing defeat in his home state of Florida on Tuesday, one that effectively closed off any path to the required number of delegates needed to secure his party's nomination later this summer.

Rubio finished in second place, far behind real estate mogul Donald Trump . Sen. Ted Cruz (R-Texas) followed in third place, with Ohio Gov. John Kasich coming in last.

"After tonight, it is clear that while we are on the right side this year, we will not be on the winning side," Rubio said during a press conference in Florida. "While this may not have been the year for a hopeful and optimistic message about our future, I still remain hopeful and optimistic for our country."

The senator further condemned the politics of anger and fear that have consumed the party, blaming the political establishment, which he said "looked down on conservatives as simple-minded people" and took "the votes of conservatives for granted."

Rubio's stinging defeat is major blow to the establishment wing of the GOP, which coalesced around the young Florida Republican and his message of generational change as their best opportunity to retake the White House in November. Tuesday's resounding defeat in Florida also puts Rubio's political future in jeopardy. He decided early on not to run for re-election for Senate in 2016, and the big loss in his home state could make a gubernatorial run exceedingly difficult.

Rubio entered the GOP presidential primary in April, announcing his campaign at Miami's Freedom Tower, an emblem of Cuban-American heritage. The eloquent and telegenic senator came out swinging at Democratic front-runner Hillary Clinton as being beholden to the politics of the past.

"Just yesterday, a leader from yesterday began a campaign for president by promising to take us back to yesterday," Rubio said. "But yesterday is over, and we are never going back. We Americans are proud of our history, but our country has always been about the future."

It's an argument that could have proved very effective against the 68-year-old presumptive Democratic presidential nominee, who has struggled to appeal to young voters more enamored with scandal-free rival Sen. Bernie Sanders (I-Vt.).

But if anything, Rubio's platform was substantially more backwards-looking -- an ironic twist given his campaign slogan to usher in a "New American Century." To the disappointment of Rubio and his party, the Florida senator never made it out of the crowded circus that was the 2016 GOP primary to find out.

As a member of the Senate Foreign Relations Committee, Rubio presented himself as an extremely hawkish voice with the foreign policy expertise needed to navigate a period of heightened global unrest -- a playbook that proved effective in previous GOP campaigns for the White House. He flip-flopped on immigration -- an issue he once championed in the Senate by helping write a bill that provided undocumented immigrants a pathway to citizenship. He took a hardline stance against gay marriage and abortion -- even opposing exceptions for rape, incest and protecting the life of the mother. He refused to acknowledge the reality of the scientific consensus around climate change -- a particularly worrying issue in Florida.

Throughout his campaign, he remained relatively steady in the polls as other conservatives entered and exited the GOP primary, and therein lay the problem. He was consistently the most popular second choice among Republican primary voters, a made-for-TV candidate who placed a greater focus on winning the Fox News primary rather than the business of campaigning. He never won a major primary state.

Rubio's biggest problem, ultimately, may have been Cruz and Trump, who outflanked him at every turn despite a near-perfect record in 12 presidential debates (a rare misstep on stage in February led to a disastrous fifth-place finish in the key New Hampshire primary). Picking up where former presidential candidate Florida Gov. Jeb Bush's super PAC left off -- the group spent millions in television ads against Rubio in the Sunshine State -- Cruz and Trump savaged the young senator for his poor attendance record in the Senate and his previous work on comprehensive immigration reform.

It was Trump and his propensity to hurl personal insults, in particular, that brought the senator to his lowest point in the race on the eve of the Florida GOP primary. In a puzzling bid for media attention, Rubio questioned the size of Trump's manhood, vis--vis the size of the real estate mogul's hands. Trump in return took to calling the senator "Little Rubio" -- mocking him for his height and boyish looks.

It was a strategy Rubio himself regretted.

"In terms of things that have to do with personal stuff, yeah, at the end of the day it's not something I'm entirely proud of," he said. "My kids were embarrassed by it, and if I had to do it again I wouldn't."

To add even more insult to injury, Rubio alluded to the significance of Trump's win in Florida in a plea to supporters last week.

"I need your help," he said . "I believe with all my heart that the winner of the Florida primary next Tuesday will be the nominee of the Republican Party ."