There are two primaries today, Michigan and Arizona. Michigan has been in the news almost daily. The bulk of the news reporting is on Michigan. Polls in Arizona give Romney a double digit lead over Santorum. The reasons are (I suppose) that Michigan polls are tight, that Michigan is Romney's home state, the candidates are spending most of their time in Michigan, and the Michigan has more Presidential electoral votes in the general election. However, this is the Republican primaries. Notice: Michigan has 30 delegates to give; they are awarded proportionally to how the primary vote is counted. Arizona has 29 delegates to give, they are awarded winner take all. So Romney figures to get about 42 delegates today, and Santorum perhaps 12 delegates.