Claims of a decisive 'turning point' in any election are often overblown - more often, such a moment merely crystallizes a change that's been days or weeks in the making. But you can make a real case that Obama's Jefferson-Jackson Day speech is a pivot point in America history.

The 2008 battle in Iowa for the Democratic caucus was perhaps the most titanic single nominating contest in the history of modern politics.

Barack Obama's convention speech in 2004 had made him a political star, and he arrived in Iowa to crowds unseen in caucus history.

John Dickerson Quotes