Republicans will be heading to the polls today in Michigan and Arizona to choose a preferred GOP nominee for president. Polling data in Michigan indicates the race is very close between Rick Santorum and Mitt Romney while Arizona tells a different story where Romney leads significantly.

Poll Closing Times:
Michigan – 8pm ET
Arizona – 7pm MT (9pm ET)

Report from the Washington Post:

Today is primary day in the two big states before Super Tuesday, Arizona and Michigan. They’re both states that Mitt Romney had been expected to win easily – until Rick Santorum began gaining momentum among conservative voters as the “not-Romney” alternative.

Of the two, Michigan is by far the more competitive race – the candidates have been spending the bulk of their time there in recent days, and both Romney and Santorum hold their primary-night parties there tonight.

Santorum holds events today in Grandville and Kentwood, Mich., then makes a swing over to Perrysburg, Ohio, before returning to Grand Rapids in western Michigan for his primary night rally.

Romney starts off the day in Livonia, Mich., and holds his primary night rally in Novi, 30 miles west of Detroit. (Sen. John McCain (R-Ariz.), one of Romney’s top surrogates, visits a Romney primary-night party in Phoenix on the candidate’s behalf.)

Newt Gingrich, who all but bypassed Michigan, is spending the day in his home state of Georgia, where he holds three campaign events, two news conferences and a primary night rally.

And Rep. Ron Paul, who campaigned only lightly in Michigan, is spending his primary night in Springfield, Va.

We’ll have the results this evening though I’m betting a winner in Michigan will not be declared until late into the night. Arizona may be easier to call if Romney’s support holds as the polling data indicates.