WASHINGTON — She had everything going for her. The most famous name in politics. A solid lead in the polls. A war chest of at least $133 million. Yet Hillary Clinton now finds herself struggling for political survival, her once-firm grasp of the Democratic presidential nomination seemingly slipping away. What happened? Barack Obama, for one thing, a uniquely gifted speaker with a face that appeals deeply to the Democratic Party. He also had a better-organized campaign. But Democrats say that Clinton, whose central theme is her readiness to be president, also made blunder after blunder. She chose an inexperienced campaign...