Stephanie Condon Stephanie Condon is a political reporter for CBSNews.

While the polls leading up to Tuesday have shown a tight race in Michigan, the CBS News early exit polling shows that Romney's supporters so far are more enthused about their candidate than Santorum's supporters are: 53 percent of Romney's Michigan supporters say they strongly favor him, while 37 percent have reservations about him.Nearly eight in 10 Romney supporters in Michigan say they will definitely support the Republican nominee in the fall.

Viewer's guide: The Michigan primaryEstimated Republican Delegate ScorecardBy comparison, 39 percent of Santorum's Michigan supporters say they strongly favor him while nearly one in five say they are supporting the former senator because they dislike the other candidates.Fewer Santorum supporters say they will definitely back the GOP nominee in November.

Watch Santorum at left discuss whether the Michigan primary is "must win" for his campaign.

Not surprisingly, in both Michigan and Arizona, the economy is the issue voters care most about, the early exit polling shows.In Michigan, 54 percent called the economy the most important issue.

Another 24 percent called the federal budget the most important issue, while 14 percent named abortion and 3 percent said illegal immigration.

In Arizona, 48 percent said the economy is the most important issue, while 32 percent named the federal budget, 12 percent said illegal immigration and 6 percent said abortion.And now, 'Oh, I'm gonna run for the Republican nomination for president, I'll be a conservative today.

' What's he gonna be tomorrow?" .recirc_item:nth-child(5) { display: none; } #recirc_item_d2b7b65c-8c88-11e2-b06b-024c619f5c3d { display: none; } #recirc_item_d2b7b65c-8c88-11e2-b06b-024c619f5c3d ~ .

recirc_item:nth-child(5) { display: list-item; } First published on February 25, 2012 / 8:47 PM © 2012 CBS Interactive Inc.All Rights Reserved.

Lindsey Boerma Lindsey Boerma is senior video producer for CBSNews.