There has not been a primary contest since February 11th, when Maine finished their caucus. Earlier that week, Rick Santorum, came to a surprise top finish in three states, Missouri, Minnesota and Colorado. Since then, the race quickly turned into a contest between Mitt Romney and Rick Santorum.
The 17 day lag between Maine's caucus and tonight was the longest break in the primary contest to date. Initially after the win, Santorum had a wide boost in publicity and popularity, and was polling ahead of Romney in Michigan. However, Romney had some great strengths in the state, such as the fact that his father had been governor there and that Mitt Romney himself had been born there. Romney also has a lot of money to spend, and many influential backers to endorse him. In addition, as Santorum became a more prominent candidate, more questions about his history and beliefs surfaced. Also, Santorum probably suffered from the fact that when an underdog starts winning, they by definition lose part of their appeal.
In the day or two before the race, the polls showed a slight lead for Romney. When it came time for the actual votes to come in, Romney and Santorum were fairly close in the vote, although as the urban and suburban areas that were Romney's strongholds started reporting in, he pulled slightly ahead. As it stands right now, with 99.7% of precincts reporting, Romney has 41.1% of the vote, Santorum has 37.9%, with Ron Paul and Newt Gingrich getting the remainder of the vote.
Michigan allocates its delegates based on congressional district, so although Romney won a greater share of the popular vote, there is a possibility that Santorum could have actually won more delegates. Despite that, the contest will still be considered a victory for Romney.
As of tonight, and even more so, next Tuesday, the contest is settling down into a somewhat predictable pattern. It seems that neither Romney nor Santorum can win over the entire party, but that conservative, rural and lower income voters will probably vote for Santorum, while middle class and suburban voters will vote for Romney. If tonight's result in Michigan is an indication of things to come, while the race is still not totally clear, the basic demographic outlines of where the candidates will draw their strength from has now come into focus.