In the space of 48 hours, two political scions will announce their candidacy for president of the United States.

Hillary Clinton, the wife of former president Bill Clinton, and a New York senator and U.S. secretary of state in her own right, formally launched her presidential campaign in a picture-perfect event on Roosevelt Island in New York City on Saturday.

Jeb Bush, the son of former president George H.W. Bush and the brother of former president George W. Bush, announced that he is formally a candidate for president in Miami later today.

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But the real momentum is with neither Clinton nor Bush. It’s with Bush’s one-time protégé, Florida senator Marco Rubio. At 44, he’s around two decades younger than either Bush (62) or Clinton (67), and it’s an advantage he is using to full effect.

Despite the sense that nearly every major Republican office-holder is running for the presidency in 2016, there are really just a handful of serious contenders that could become president — and even some of them have flaws. Former Texas governor Rick Perry may have a great story about low-tax, low-regulation governance, but it’s hard to believe anyone will give him a second look after his ill-advised, disastrous 2012 campaign. Ohio governor John Kasich would have been a credible contender if he’d started running earlier. With every passing day, it looks like one-time frontrunner New Jersey governor Chris Christie won’t even run. Carly Fiorina is proving a quick study, but her entire political experience involves losing a Senate race in California. Kentucky senator Rand Paul’s principled live-and-let-live libertarian views may become the future of American conservatism, but too many Republican constituencies would undoubtedly line up in an anyone-but-Rand coalition. South Carolina senator Lindsey Graham is running on a full-fledged neoconservative brand that may prove a skeptical sell even to hawkish Republicans.

Other candidates will sound populist calls in appeal to frustrated ‘tea party’ voters (Louisiana governor Bobby Jindal and Texas senator Ted Cruz) and religious conservatives (former Arkansas governor Mike Huckabee and former Pennsylvania senator Rick Santorum). However smart or charismatic they are, none have a credible shot of both winning the Republican nomination and beating Clinton in the general election.

After all the smoke subsides, three real contenders emerge: Bush, Rubio and Wisconsin governor Scott Walker.

Bush, a moderate viewed with suspicion by his party’s grassroots for his centrist positions on education and immigration reform, last contested an election in 2002, and he aims to be the third member of his family to occupy the Oval Office in the same quarter-century.

Walker is a conservative who relished the opportunity to attack Wisconsin’s powerful public sector unions, but there’s no indication that he has the kind of charisma to defeat Clinton or that his take-no-prisoners conservatism will play better than Clinton’s pragmatic centrism.

Rubio, however, brings together some of the most significant attributes of both a Bush or a Walker nomination, and he adds further assets that neither Bush nor Walker have. Like Bush, Rubio will boost the Republican ticket in his home state of Florida, a crucial Electoral College battleground, and both Bush and Rubio understand the importance of expanding the Republican base, especially among Latino voters. Like Walker, Rubio is broadly acceptable to both the pro-business Republican establishment and the more populist grassroots and ‘tea party’ elements of the party.

Rubio’s youth allows him to draw a contrast with Clinton, a distinction Rubio is already skillfully deploying. Though, like Barack Obama, he is aspiring to the presidency as a first-term senator, he has nine years of experience in the Florida House of Representatives, two of those as its speaker.

His personal background as the son of Cuban immigrants means that Rubio would become the country’s first president of Latino origin. That doesn’t necessarily mean that he’ll win the votes of Hispanics across the United States — Cuban Americans in Florida are much different, as a voting bloc, than first-generation Salvadoran Americans in Los Angeles or fourth-generation Mexican Americans in south Texas. But it’s a good start for a party that desperately needs to expand its base, especially if Rubio embraces the kind of open-hearted conservatism most associated with the late Jack Kemp.

He could sharpen his policy focus and, if he wins the nomination, he should consider co-opting a couple issues that could boost Republican fortunes — by making peace on the issue of LGBT marriage equality, for example, or embracing universal maternity leave or a market-based approach to reducing carbon emissions. Rubio’s views on foreign affairs still lean toward the neoconservative, which will be a hard sell to an electorate still weary of U.S. entanglements in Iraq and Afghanistan.

Above all, his position on immigration reform is muddled, it’s true, and Walker and others on the right will pounce on Rubio for that. But it’s clear enough that Rubio prefers a fix that falls short of ‘amnesty,’ which nonetheless doesn’t deport millions of people who have created new lives in the United States, and that could make Rubio a very attractive general election candidate.

Even revelations about Rubio’s supposed personal financial troubles, as reported last week by The New York Times, might wind up helping him. That he spent $80,000 on a boat and struggled with mortgages and student loans? Far from disqualifying Rubio from the presidency, it makes him seem like any other aspiring, middle-class guy from south Florida — a much more relatable candidate than, say, a millionaire like Mitt Romney.

None of this is to say that Rubio is a lock for the nomination or for the presidency in November 2016. But the gauntlet is certainly somewhat less difficult for him than for the rest of the historically crowded Republican field.