As long ago as 2003, the Clintons’ pollster, Mark Penn, was quietly measuring Hillary’s presidential appeal, with an eye toward the 2004 election. Polling suggested that her prospects were “reasonably favorable,” but Clinton herself never seriously considered running. Instead, over the next three years, a handful of her advisers met periodically to prepare for 2008. They believed the biggest threat was John Edwards.

Decisions made before her 2006 reelection to the Senate were to have important consequences downstream. Perhaps the biggest was Clinton’s choosing to forgo the tradition of visiting early states like Iowa and New Hampshire. Even if she was presumed to be the heavy favorite, Clinton needed to win Iowa to maintain the impression of invincibility that she believed was her greatest advantage. And yet Iowa was a vulnerability. Both husband and wife lacked ties there: Bill Clinton had skipped the 1992 caucuses because Iowa’s Senator Tom Harkin was running; in 1996, Clinton had run unopposed.

With her Senate race looming, she feared a backlash if she signaled her presidential intentions. If New Yorkers thought her presumptuous, they could punish her at the polls and weaken her national standing. A collective decision was made not to discuss a presidential run until she had won reelection, leaving the early pursuit of Iowa to John Edwards and Barack Obama.

The effect of these choices in Iowa became jarringly clear when Penn conducted a poll just after Clinton’s Senate reelection that showed her running a very distant third, barely ahead of the state’s governor, Tom Vilsack. The poll produced a curious revelation: Iowans rated Clinton at the top of the field on questions of leadership, strength, and experience—but most did not plan to vote for her, because they didn’t like her. This presented a basic conundrum: Should Clinton run a positive campaign, to persuade Iowans to reconsider her? Or should she run a negative campaign that would accuse her opponents of being untrustworthy and under-qualified? Clinton’s top advisers never agreed on the answer. Over the course of the campaign, they split into competing factions that drifted in and out of Clinton’s favor but always seemed to work at cross purposes. And Clinton herself could never quite decide who was right.