That announcement came on the heels of a "significant" victory in his home state of Florida for GOP front-runner Donald Trump, as projected by NBC News. At 44, Rubio was touted earlier in the campaign as one of the brightest young stars of the Republican party.
But Rubio, with wins in just Minnesota, Puerto Rico and the District of Columbia, lamented in a Tuesday address that it was "clear" he would not be on the winning side of history, but he continued to promote the thesis of his campaign: A political run that is "realistic about the challenges we face," but still "optimistic."
"While it is not god's plan that I be president in 2016 — or maybe ever — and while today my campaign is suspended, the fact that I've even come this far is evidence of how special America truly is, and all the reason more why we must do all we can to ensure that this nation remains a special place," Rubio said.
"I ask the American people: Do not give into the fear, do not give into the frustration," he added, potentially referencing some of the perceived vitriol that other Republican hopefuls have mustered.
Pundits had for weeks deemed Rubio the "establishment" favorite in the GOP race after his one-time mentor former Florida Gov. Jeb Bush dropped out of the race. When Bush, whose campaign and super PACs had won much of the race's early donor cash, suspended his run, Rubio's campaign had seemed the heir apparent.