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 would pretty much completely disagree with you on that. I'm from Iowa. Iowa was the state that "made" Barack Obama into a legitimate contender for the Democratic presidential nomination. People forget quickly just how important his Iowa caucus victory was, how much it changed the entire discussion about his candidacy and his ability to appeal to "middle-American" (white) voters. A great many Iowans take pride in the fact that they "launched him" into the national consciousness through his caucus victory. There is without any doubt whatsoever more of a connection between Iowa voters and Barack Obama than between voters in Missouri or any other state besides perhaps Hawaii or Illinois.
And besides, I didn't say that the loyalty and connection that Iowa voters have with Obama is the only, or even the primary reason, why white Iowans were more likely than white Missourians to vote for him. The other reasons have already been stated in this thread. White Iowans are more progressive, less religious, and less racist than white Missourians. White Missourians probably vote a lot like white southerners. White Iowans vote more like white Minnesotans or white Wisconsinites. But Obama did better among white Iowans than even among white Minnesotans or white Wisconsinites. Why? Because Obama has a stronger connection with Iowa than he does with Minnesota or Wisconsin.
