Iowa and Missouri are not that much alike, even though they share a border. But a big part of it was the candidate. Iowa was the state that gave Obama his first major victory as a presidential candidate. Iowans probably felt more loyalty to Obama than Missourians did, due to the connection that Obama had with Iowa.
I don't think the result of the primary of 2008 has anything to do with the result of this year's presidential race, and loyalty and connection is not something very much shared among the broad load of voters...
