Mitt Romney enjoys a double digit lead in the polls in Arizona today but is in trouble in Michigan.
Since we ran the Michigan numbers early Monday morning, three new polls are out that make the state look more like a true toss-up and less like one that favors Mr. Romney.
Two of the surveys, from Mitchell Research and American Research Group, in fact give Rick Santorum a nominal lead in Michigan, by 2 and 1 percentage points respectively. The third, from Rasmussen Reports, gives Mr. Romney a 2-point advantage.
We also added a hard-to-track down survey from Baydoun Consulting, which gave Mr. Romney an 8-point advantage. However, it is less recent than the others, having been conducted on Thursday night rather than over the weekend.
Among the five polls that were conducted over the weekend -- including those that had been included with the previous update -- three give Mr. Romney a small lead while two show an edge for Mr. Santorum.
Mr. Romney still has the advantage in the FiveThirtyEight forecast, but it is more tenuous than the one we released overnight. The model gives him a 64 percent chance of winning the state, down from 77 percent in the previous forecast.
One thing not mentioned by Mr. Silver is the enthusiasm gap between Santorum voters and Romney voters. In a very tight race like this, the winner will be he who can get a larger share of his supporters to the actual polls to vote. Romney has the money to run a good GOTV operation, but Santorum's supporters appear more committed and thus more likely to show up to vote for him.
It will likely be a long night tonight in Michigan.