“Too many of our leaders and their ideas are stuck in the twentieth century,” Rubio told a the crowd gathered at the Freedom Tower, a sort of Ellis Island for Cuban exiles like his parents. “They are busy looking backwards, so they do not see how jobs and prosperity today depend on our ability to compete in a global economy. So our leaders put us at a disadvantage by taxing, and borrowing, and regulating like it was 1999.”

At 43, Rubio stands as the youngest contender in what could reasonably be considered the contest’s first tier. Judging by the speech, he won’t let his elders soon forget it. “They look for solutions in yesterday,” he went on. “Now the time has come for our generation … It is a generational choice … Yesterday is over and we are never going back … Our country has always been about the future … We can’t do that by going back to the leaders and ideas of the past.”

Amid jabs at The Olds, Rubio weaved in stirring references to his own story as the son of Cubans who fled to America seeking a better life for their children. That narrative of humble beginnings — his dad was a bartender, his mom a cashier and a maid — carries its own weight. But it also underscores the departure Rubio aims to represent from the dynastic hold that the Bush and Clinton clans claim on our politics.

The newly-minted White House hopeful also offered up some boilerplate about unleashing prosperity at home while projecting strength overseas. But this speech was all about atmospherics. As our recent history demonstrates, youth and change can make for a potent electoral combination. A key for Rubio, now apparently running only third in his home state, will be satisfying a threshold question in the minds of voters about his readiness for the job. His highest-profile foray into policymaking during his four years in Washington — as a leader of the bipartisan immigration reform effort in 2013 — passed the Senate but died in the House in the face of right-wing rage. With his support among conservatives cratering, Rubio abandoned the comprehensive approach he’d coauthored in favor of a border security-first hardline. The accommodation regained him no love from the base while sacrificing the good faith he’d earned from Hispanics. In other words, it proved a lose-lose.

Yet the former state House speaker has outrun expectations his entire career in public life: He won his senate seat, for example, in the face of near-total opposition from Florida’s Republican establishment, which aligned in the primary behind the moderate former Gov. Charlie Crist. No surprise, then, that Rubio has hustled since the immigration debacle to try to make up the ground he lost.

From his perch on the Foreign Relations Committee, he’s voiced a hawkish line on international affairs while other ascendant personalities in the party, most notably 2016 rival Sen. Rand Paul (R-Ky.), have advocated for American retrenchment abroad. And on the home front, he has pressed forward with an economic vision, linking with fellow freshman Sen. Mike Lee (R-Utah) to propose a wholesale overhaul of the tax code. The framework they crafted earned them praise from some reform conservative brains — and also some friendly fire. New York Times columnist Ross Douthat argued the plan — which combines some family-friendly provisions, like an expansion of the Child Tax Credit on the individual side of the code, with red meat like a top corporate rate slashed to 25% — could cost the Treasury up to $4 trillion over a decade and is therefore “simply not reasonable given America’s current fiscal situation.” (Rubio, for his part, argues that accounting doesn’t credit the proposal with the economic growth it would unleash, though whether that would make more than a slight dent in the overall price tag is dubious.)

The policy debates will be joined later. As Rubio all but spelled out in caps lock Monday night, he’s going to do what he can in the meantime to make his front-running competition feel their age.

For more on the presidential campaign, watch this Fortune video about Hillary Clinton: