For a sign of the GOP worries, just look at whose names have cropped up in the last month as prospective candidates: Mitt Romney and Jeb Bush. It's a direct result of the growing anxiety that Republicans lack a statesman-like candidate who can compete with Hillary Clinton on stature. Romney's prescient warnings during the 2012 presidential debates about the geopolitical threat posed by Russia and the risk of prematurely withdrawing troops in Iraq have sparked a wave of nostalgia for a third campaign. He's even stoked the speculation a bit, by suggesting that he wouldn't entirely rule out another run—however remote the possibility.
Meanwhile, Jeb Bush's inner circle is teasing out renewed interest in a campaign to Politico's Mike Allen, who noted that the former Florida governor is receiving "foreign policy tutoring" as part of his prep work. The younger Bush is known more for his advocacy on immigration and education reform, but by virtue of his last name, will always be connected to his brother's foreign policy legacy. That was once a major vulnerability, but the Bush brand has been somewhat rehabilitated as President Obama finds himself engaged in the "war on terror" that he spent most of his tenure downplaying.
Neither Romney nor Bush, whether they run or not, would be favored to emerge as the nominee. Romney's favorables are still underwater and he's a symbol of the GOP's past, not its future. Bush is out of step with the party's base on numerous issues, and has a rusty political antenna. But their interest is in direct response to the muddled GOP field. Right now, having a deep bench isn't as valuable as having a few seasoned contenders.
Rubio is the most intriguing Republican to watch going forward, with national security reemerging as a top issue. He took a risky vote last week supporting the president's authorization to arm Syrian rebels, while Paul and Sen. Ted Cruz opposed it. He's comfortable speaking off the cuff about foreign policy, and his muscular internationalism is squarely in line with prevailing GOP sentiment. His speech at the John Hay Initiative this month calling for increased defense spending was well-received by conservatives, and could serve as a blueprint for the senator's vision. His biggest challenge is proving he has the experience, after one term in the Senate, to be taken seriously.
Then there are the two Republican contenders whose blunt, no-nonsense governing style could be channeled into a tough-on-terrorism image: New Jersey Gov. Chris Christie and Texas Gov. Rick Perry. Christie's specific views on foreign policy are unclear, but he's hinted that he hails from the hawkish wing of the Republican Party. Last year, on a Republican governors' panel, he criticized Rand Paul for challenging government surveillance programs and being naive about the threat of terrorism. Governing New Jersey, where the threat of terrorism is acute, gives him an advantage on national security over his gubernatorial counterparts.