DES MOINES, Iowa — Three high-profile Republicans from the party's mainstream are suddenly competing for the same group of elite donors and staffing talent with Mitt Romney's launching a third run for president in 2016 elections. And that list — Romney, New Jersey Gov. Chris Christie and former Florida Gov. Jeb Bush — doesn't even include a group of Midwestern governors, led by Wisconsin's Scott Walker, who also fit the mold of accomplished, economic-minded executives driven as much by a pragmatic approach to governing as their conservative ideology. In the race for the Democratic nomination, Hillary Rodham Clinton has emerged as an early front runner, although she has not yet declared her candidacy. Nor have any of the ambitious Republicans formally entered the race yet. But more than a dozen candidates are preparing for what is widely seen as a once-in-a-generation opportunity — an open White House and no Republican heir apparent with a claim to the nomination. The abundance of Republican presidential prospects who put economic policy ahead of social issues comes after Republican congressional leaders succeeded last year in beating back primary challenges from farther-right, tea party-affiliated candidates on their way to reclaiming control of the Senate. It also sets up a potential contest of mainstream Republicans not seen since 2000, when George W. Bush was the favorite in a crowded field, or 1988, when then-Vice President George H. W. Bush was the heavy favorite. Romney's potential leap into the race seemed unthinkable a week earlier, when Bush and Christie were seen as more than capable of satisfying the establishment's desire for mainstream candidates with White House-worthy resumes. “By and large, they're all going after the same base (of donors),” said former Missouri Sen. Jim Talent, a senior adviser to Romney's 2012 campaign and among those he called in recent days to talk about another run. “One of the things you have to determine is whether you can raise the money, and I think that's one of the things he's calling around about now,” Talent said. “I would feel pretty confident about that with him. He's always been pretty good at mobilizing support.” A spokeswoman for Jeb Bush welcomed Romney to the race this week, but she suggested the former Massachusetts governor efforts wouldn't affect Bush's own plans. — AP