As late as last weekend, Mr. O’Rourke had still not settled on who would guide his campaign. He discussed the campaign manager job for 90 minutes with a Democratic strategist, Jennifer O’Malley Dillon, at the South by Southwest festival in Austin, but even on the eve of his announcement it was uncertain who would be at the helm of his organization.
Yet he enjoys the support of many of former President Barack Obama’s aides, some tacitly and others more full-throated, and he has relied on advice from a number of Mr. Obama’s strategists, including the 2008 campaign manager, David Plouffe. (Mr. Plouffe is not, however, planning to formally participate in the race on behalf of any candidate.)
But unlike Mr. Obama, who ran in a year when the Iraq war was the single overriding policy issue in the Democratic race, Mr. O’Rourke is seeking the presidency at a moment his party is lurching left across the board. He will be immediately under pressure to expand upon the sometimes-vague liberalism that has colored his public life.
Already, allies of Mr. Sanders in particular have questioned Mr. O’Rourke’s commitment to progressive priorities. (Mr. O’Rourke has declined to call himself a progressive, saying he was “not big on labels.”)
In 2016, he supported a centrist challenger to Nancy Pelosi to lead House Democrats. In 2018, he frustrated Texas activists by refusing to endorse Gina Ortiz Jones, a prized Democratic recruit for a House seat, because she was facing Mr. O’Rourke’s Republican friend, Representative Will Hurd, who eventually won by fewer than 1,000 votes.
And while Mr. O’Rourke should have little trouble pulling in enough money to get a presidential campaign off the ground, it is not clear precisely how he will fare in fund-raising in such a large field of Democrats, without a binary contest against Mr. Cruz, whom liberals love to loathe.
Some in the party have questioned whether a Senate-race-losing candidate like Mr. O’Rourke should even be running for president so soon. Several have encouraged him to seek statewide office again; Senate Democrats aggressively lobbed him to take on Texas’ other Republican senator, John Cornyn, who is up for re-election next year, even dispatching senior party officials to El Paso to make the case.