Bush, for his part, knew from the beginning that he’d need to distinguish himself from his father and brother’s presidencies.

He had an I-am-my-own-man answer practiced and ready to go.

Yet he still managed to fumble questions about whether he’d have invaded Iraq as his brother did. And his turns of phrase about “evil-doers” and the burdens of presidential decision-making clearly echo those of his brother George W. Bush, undercutting his efforts to distinguish himself.

In both Clinton and Bush’s cases, says Schnur, no matter how hard campaigns try to anticipate challenges and be ready for them, “It always sounds better at campaign headquarters than it does out on the trail.”

“It’s not that hard to sit in a conference room and strategize about how to handle a potential problem,” Schur said. “The problem is the other candidates and the media and the voters don’t always react to that strategy the way you want them to.”