Sen. Marco Rubio formally announced his candidacy for president Monday, making him the third Republican to enter the 2016 presidential race. Against the backdrop of Miami’s Freedom Tower, a location symbolic to Cuban refugees fleeing an oppressive regime, Rubio laid down a challenge for America to reclaim its place in the world.

“Before us now is the opportunity to author the greatest chapter yet in the amazing story of America,” Rubio declared. “But we can’t do that by going back to the leaders and ideas of the past.” This was a not too subtle jab at Hillary Clinton, who Rubio later mentioned more directly as the wrong choice for America. “Just yesterday,” he said, “a leader from yesterday began a campaign for president by promising to take us back to yesterday. Yesterday is over, and we are never going back.”

Rubio has outlined some policy proposals in the past that include expanding the Child Tax Credit and giving states more say in their federally funded health care and poverty programs, but it is national security where Rubio seems to be staking his claim for the presidency.

In his four years in the Senate, Rubio has served on the Foreign Relations and Intelligence committees. He has sought the advice of foreign policy experts from the administrations of George W. Bush and Ronald Reagan. He has spoken often of the importance of Liberty in the world and for America to project its foreign policy decisions from a position of strength. His background as the son of Cuban immigrants — a bartender and a hotel maid who lived the American Dream — is widely considered to be a principal motivator in his concern for freedom.

“I am humbled by the realization that America doesn’t owe me anything,” Rubio said, “but I have a debt to America I must try to repay. This isn’t just the country where I was born; America is the place that changed my family’s history.”

Former Reagan senior diplomat Eliot Abrams said, “The whole question of the expansion of freedom of democracy is of greater interest to [Rubio] as a foreign policy theme than it is for many other people.”

Rubio openly questioned Barack Obama’s overtures to the Castro regime in Cuba, and he was among the first to point out that Obama was giving away the store to the Castros while getting essentially nothing in return. Of the recent gathering at the Summit of the Americas, Rubio wrote in National Review that the appearance of Raul Castro made a mockery of the gathering of leaders of the hemisphere’s democratic nations: “Allowing a brutal dictator to attend undermines the future of democracy in the region. Already we’ve seen more evidence of the summit’s being influenced by Cuba than of Cuba’s being influenced by the summit’s principles supporting democracy.”

Rubio has accomplished much in his young political career, but his road to the White House is a steep climb. His youth and energy are attractive and have given him name recognition, but many people are skeptical of giving the keys to 1600 Pennsylvania Avenue to another freshman senator (a status shared by the other two announced candidates). Rubio’s age advantage is also blunted by the relative youth of the entire Republican field.

Rubio displays prodigious fundraising talent, but he will be competing against Jeb Bush’s massive operation. Even though Bush has yet to formally announce his candidacy, he has locked up key supporters and established a national fundraising operation that will be tough to beat.

Rubio’s laying it all on the line. Florida law demands he give up his Senate seat in order to run for president. Should he lose, he will have to fight his way back into politics, though a Rubio governorship isn’t out of the question — especially considering that would set him up for a stronger White House run in the future.

Rubio is also an attractive vice presidential candidate. He was on Mitt Romney’s short list in 2012, and we could see him matched up this time around with Scott Walker or Rick Perry. But a Bush win ends Rubio’s VP chances because the Constitution precludes the president and vice president from calling the same state home.

Whatever the outcome, Rubio’s entrance into the race furthers a broader debate with fresh perspectives about the direction of the country. That’s never a bad thing.