Michigan and Arizona primary results: Mitt Romney re-established himself as the Republican front-runner Tuesday night with his win in Michigan’s pivotal primary, fending off what would have been a crushing defeat by rival Rick Santorum.

Mitt Romney's Speech on Michigan Primary Win: 'We Won by Enough'

◼ Michigan and Arizona primary results - Le·gal In·sur·rec·tion

◼ Mitt Romney swept to victory in the Arizona primary and led Rick Santorum in a close, hard-fought contest in Michigan Tuesday night, bidding for a two-state sweep and fresh momentum in the race for the Republican presidential nomination. - AP

Romney's Arizona triumph came in a race that was scarcely contested, and he pocketed all of the 29 Republican National Convention delegates at stake.

◼ Romney-Santorum Locked in Tight Michigan Race – 9% of Voters Are Democrats - Gateway Pundit

◼ Exit polls: 1 in 10 voters was a Democrat in Michigan primary - LA Times

Initial exit polling in the Michigan primary suggests that in a tight battle between Mitt Romney and Rick Santorum, the votes of Democrats could prove decisive in the key Republican presidential skirmish -- and more of those votes are going to Santorum.

According to CNN, 10% of those who voted in the primary identified themselves as Democrats, representing a larger share of the electorate than in the 2008 vote. Of that group, 50% said they voted for Santorum, 19% for Ron Paul and 15% for Romney, exit polling showed.

That result would suggest that the combined efforts of the Santorum campaign and state Democrats to appeal to the left were successful, though their motivations were different.

◼ Open thread: Michigan and Arizona; Update: Romney projected winner in both states - Michelle Malkin

◼ After tough race, Romney beats Santorum in Michigan primary - The Hill

◼ Romney Wins in Michigan, Arizona - Wall St. Journal

◼ Santorum fails to stop Romney in Michigan - Susan Ferrechio/Washington Examiner