He famously called Obama's contention that he consistently opposed the war in Iraq a "fairy tale," repeatedly served up questionable assertions about his wife and her opponent, and equated Obama's strong showing in South Carolina with that of Jesse Jackson, in comments that drew a harsh backlash that may have cost his wife African-American support in the remaining contests.
A team of longtime Clinton loyalists formed the core of the campaign, with Mark Penn playing the unusual dual role of chief pollster and chief strategist mainly on the strength of his prior relationship with Bill Clinton.
Staff infighting — often with Penn at the center of controversy — left the campaign virtually paralyzed at critical junctures, with major strategic changes coming too late to make a major difference. Patti Solis Doyle left her post as campaign manager in mid-February — contributing to an internal and external sense of campaign turmoil.
Mark Penn was stripped of his formal campaign title in April, after he was revealed to have worked for a trade pact Sen. Clinton opposed. And Bill Clinton, of course, was the one strategist and surrogate who could not be fired, and while he may have brought his wife more votes than he lost, he left the campaign repeatedly off-message.
5. MATTERS OF TRUST
Clinton entered the race needing to overcome years' worth of questions about the Clintons' credibility — in addition to one very big vote in favor of the Iraq war.
While she made great strides in advancing her own reputation — and overcoming liberal skepticism of her campaign — a few slips renewed questions about her candidacy at the worst possible times.
The campaign's trajectory took a sharp turn on Halloween, in Philadelphia, with a straightforward debate question about a plan in New York State to give driver's licenses to undocumented immigrants.
Clinton gave a halting, contradictory response, and her campaign took weeks to put it behind her. It underscored an image of a coldly calculating, excessively cautious politician, and gave Obama, John Edwards and Clinton's other Democratic rivals a much-needed opening to attack Clinton's credibility and honesty.
By the time a better-organized, better-financed Obama delivered a soaring speech at a Democratic Party dinner 10 days after that debate, Clinton's frontrunner status was clearly in jeopardy.
And this spring, just when Obama was facing his campaign's biggest challenge with the emergence of the fiery words of the Rev. Jeremiah Wright, a botched story about sniper fire she supposedly braved in Bosnia called Clinton's credibility into question all over again.
Clinton would close out the primary season surprisingly strong, winning contests long after most pundits had declared the nomination fight over. But Obama was claiming the mantle of inevitability that once was Clinton's — winning by the rules she was supposed to have mastered, in the party she was supposed to have dominated.
Said one Democrat with close ties to the Clintons: "It was just hubris: They couldn't imagine her losing and him winning."