All of the potential 2016 presidential contenders must navigate between this parallel disenchantment with both of their predecessors. Hillary Clinton began that process with her memoir Hard Choices, in which she signaled she would have been tougher than Obama on Syria and Russia—but also unambiguously renounced her support for the Iraq War. In balancing diplomacy and force, aspiration and restraint, Clinton seems determined to seek what one top Democratic security thinker calls “an intermediate point between Bush and Obama.”

Republicans such as Sen. Marco Rubio of Florida, meanwhile, are already channeling Ronald Reagan’s arguments against Jimmy Carter by insisting that Obama has invited disorder by failing to provide “clear, decisive, and morally unambiguous American leadership.” But Rubio (and like-minded Republicans) face a mountainous hurdle Reagan didn’t: Many Americans now equate that brand of leadership with the discredited Iraq War. For that reason, Peter Feaver, a Duke University political scientist who served on Bush’s National Security Council, says Republicans ultimately can’t sell a more assertive approach than Obama’s without reversing the widespread conclusion that Iraq was a historic blunder. “You have to make the argument that sins of omission can be as bad or worse than sins of commission,” Feaver says.

Even hawkish Republicans may balk at that mission. Just defending Iraq inside the GOP could be tough enough. Likely 2016 contender Rand Paul is building the most forceful challenge to Republican internationalism since Sen. Robert Taft in the 1950s. Paul blames today’s Mideast turmoil on mistakes by both Bush and Obama (“both sides,” the Senator insists, “continue to get foreign policy wrong”), and pledges an isolationist-tinged foreign policy that “puts America first.”