Clinton underestimated the Democrats’ yearning for change
Despite the bullishness, her campaign team knew that the argument about winning the popular vote but being denied the nomination by party bosses would not work. What they were really hoping for was to buy enough time to allow Barack Obama to become derailed by some new scandal that would persuade the party’s super-delegates to move towards Clinton en masse. This was always unrealistic. It would also have involved Clinton insisting that there was something fundamentally unelectable about Obama, which would have done damage to the Democratic Party and to a united approach to the presidential campaign in the autumn.
I doubt there is any one moment or incident that cost Clinton the nomination. Too often in the early stages of the campaign, she was simply trotting out dull and wooden speeches — and this during a contest where rhetoric assumed a special status — and was too careful about being seen as in any way radical. Frequently, she was on the defensive and when asked about Iraq at most of her campaign stops in the initial days, her standard explanation was limp — if she had known then what she knows now she would not have voted to authorise the president to go to war in 2002. Not exactly convincing, was it?