The Michigan Primary, February 28th.

On February 28th, in the Michigan primary, the race for the GOP Nomination will experience a significant moment--either a momentous victory for Rick Santorum, or a victory for Romney, although if the latter happens, it will undoubtedly be at a lesser margin than originally anticipated. Michigan was a state which Romney originally expected to be able to take easily. However, Santorum's recent surge has put the state in doubt for Romney's campaign. According to the Washington Post, Santorum will aggressively pursue Michigan because he sees in it "the combination of working-class and socially conservative voters on which he has based his campaign." If Santorum defeats Romney in Michigan, it will be a clear example of what recent poll numbers have shown us--a virtual tie between the two. Michigan will be key as we continue the build up to Super Tuesday, and could even signal Santorum overtaking Romney in the race for the nomination.

Source: http://www.washingtonpost.com/politics/mitt-romney-faces-major-test-in-michigan-primary-once-thought-an-easy-win/2012/02/14/gIQAffpcDR_story.html?hpid=z2