Jeb Bush and Marco Rubio, once mentor and protégé, are poised to become fierce rivals for the Republican presidential nomination.
Both bring major advantages: They are from the key swing state of Florida and can woo Hispanics, now the largest minority in the United States, in fluent Spanish.
Mr. Rubio has emerged as an early front-runner among declared Republican candidates. "Some suggest that I should step aside and wait my turn," he said in April, ending speculation that he would defer to Mr. Bush.
As for Mr. Bush, he will formally announce that he hopes to follow his father and brother to the White House at a campaign launch in Miami on Monday – an event that will stress Jeb 2016, not Bush 2016.
In many ways the two candidates could not be more different – offering Republicans a choice between an old-family patrician and a make-good son of Cuban immigrants; between the standard-bearer for one of America's most powerful political dynasties and a relative unknown. Perhaps most importantly, Mr. Bush and Mr. Rubio offer a generational choice.
"The time has come for our generation to lead the way toward a new American century," Mr. Rubio said in announcing his candidacy in April. Then, taking a poke at both the presumed Democratic nominee, Hillary Clinton, and Mr. Bush, he added: "In many countries, the highest office in the land is reserved for the rich and powerful. But I live in an exceptional country where even the son of a bartender and a maid can have the same dreams and the same future as those who come from power and privilege."
Not just age differentiates Mr. Rubio, who turned 44 last week. But if he becomes the next president, he would be the second-youngest ever elected, after John F. Kennedy. (In stark contrast, if Ms. Clinton is elected, she would be the second-oldest president, after Ronald Reagan, who was 69 when he reached the Oval Office.)
Mr. Bush is 18 years older than Mr. Rubio and had already registered for the draft and met his future wife, Columba, while teaching English in a Mexican village when Mr. Rubio was born.
In the crowded and chaotic Republican field, with almost a dozen candidates declared and more waiting in the wings, Mr. Bush and Mr. Rubio are jockeying for front-runner status.
Along with Wisconsin Governor Scott Walker – the union-busting, Tea Party favourite – the two Florida centrists are the only presidential hopefuls registering double-digit support in RealClearPolitics polls.
But their performance over the past six months differs sharply. Mr. Bush, with his unparalleled name recognition, had a commanding 17-per-cent support at the beginning of the year, far ahead of everyone else; by last weekend, that support had eroded to 11.3 per cent. Over the same period, Mr. Rubio's support has more than doubled, from 4.5 per cent to 10.3 per cent.
But as the perception of Mr. Rubio as a serious candidate has grown, so has media scrutiny. He and his wife, Jeanette, a former Miami Dolphins cheerleader of Colombian descent, have racked up 17 traffic tickets since they were married in 1998, The New York Times reported. The high-school sweethearts have suffered money problems – struggling to pay back student loans, falling behind on mortgage payments, unwisely borrowing from retirement accounts. Yet Mr. Rubio also managed to splurge on an $80,000 boat.
That may help differentiate Mr. Rubio from most of the well-heeled Republican contenders. Compared with the oil-rich Bush family, with its sprawling holdings in Texas and Maine and its family trusts, the Rubios resemble many ordinary Americans, struggling with the same sort of financial problems that bedevil the average voter.
Conversely, Mr. Bush, a two-term governor from a big state, has proven executive experience. Mr. Rubio, a first-term U.S. senator (as was Barack Obama when he launched his bid for the presidency) has none.
Both have worked to shore up their limited foreign policy credentials. Mr. Rubio sounded stridently hawkish when he vowed in a speech last month to wield U.S. military might everywhere. "As president, I will use American power to oppose any violations of international waters, airspace, cyberspace or outer space," he said.
Meanwhile, Mr. Bush, who has struggled to both defend his brother's war in Iraq and distance himself from that action, was Moscow-bashing this week in advance of his formal campaign launch. "To deal with Putin, you need to deal from strength," he said, claiming the Russian President had changed since former president George W. Bush said he could see into his soul.