And then there were three . . . Republicans running for the presidency, now that Marco Rubio has made it official. Three senators, each yet to complete a first term in Washington. Three first-time presidential hopefuls, all from states well below the Mason-Dixon Line. And three gentlemen with decidedly different ways of introducing themselves to America.

First there was Texas Senator Ted Cruz, preaching faith and social conservatism at Liberty University (video here). Then along came Kentucky Senator Rand Paul with a meandering treatise on libertarianism and party outreach (video here). And now Rubio (video here).

About his kickoff, Monday night in Miami, and what it means to the GOP field.

• Age. Rubio turns 44 next month, making him the youngest Republican hopeful of serious note since a 47-year-old Richard Nixon sought his party’s nomination in 1960. It’s prompted Charles Krauthammer to liken Rubio to Nixon’s opponent that year: JFK. Said the columnist: “I think Rubio is the one – again, if the theme is new and old, I think he’s got a chance to be the sort of Kennedyesque one, a lot of energy, youth, and especially because foreign affairs have become a very important issue in the last couple of years, very unusual, that we should have an election that hinges a lot on that.” A 40-something candidate wouldn’t have much been of an issue in the formative years of the GOP (John C. Fremont, the first Republican nominee, was 43 when he ran in 1856; Abraham Lincoln was 51 when he won the presidency in 1860). However, it’s out of character with recent standard-bearers. From Reagan to Romney, the average age of a Republican presidential nominee is 66.

• “A New American Century”. Not just the slogan that was in the background for Rubio’s announcement, but an insight into his campaign’s strategy (here’s a look at where Rubio stands on a few key issues). A few days before his announcement, Rubio’s camp released this patchwork video, which is one part biography (he’s the son of Cuban immigrants – a bartender and a maid) and a second part a conservative call to arms. “This is about whether we are going to be the first generation of Americans,” he says in the tape, “to leave our children worse off than ourselves or the next generation that will allow them to inherit what they deserve, inherit what we inherited, give to them what every generation before us has given to the next: the single greatest nation in all of human history,” It has a Reaganesque ring to it. Moreover, as Rubio noted in his kickoff remarks, it separates him from other candidates who were around in the past century – a not so subtle dig at the two hopefuls whose families that have dominated national politics in post-Cold War America. On that note, reporters won’t lack for storylines of how Rubio and Jeb Bush now collide over geography, portions of the primary electorate and “Shakespearian” discomfort.

• Third Place. If you accept the consensus – Bush and Wisconsin Governor Scott Walker lead the Republican pack — then who’s sitting in third place? It may be Rubio, thanks in large part to how the chattering class assesses him. Consider this passage from fivethirtyeight.com: “Rubio is both electable and conservative, and in optimal proportions. He’s in a position to satisfy the GOP establishment, tea party-aligned voters and social conservatives. In fact, Rubio’s argument for the GOP nomination looks a lot like Walker’s, and Rubio is more of a direct threat to the Wisconsin governor than he is to fellow Floridian Bush.” Historically, third place is a terrible place to be in a Republican presidential field. But in a contest featuring a couple of wobbly frontrunners (Bush has to deal with a skeptical, sometimes hostile base; Walker polls well, but is still largely provincial), there may be something to be said about running a competitive third – for now.