Romney backs challenger in Michigan
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Former presidential nominee Mitt RomneyWillard (Mitt) Mitt RomneyDems flip Wisconsin state Senate seat Ex-adviser thinks Romney will run for Senate Jeb Bush backs Romney for Utah Senate run MORE (R) is endorsing businessman Dave TrottDavid Alan TrottGOP angst over midterms grows House Foreign Affairs chairman to retire Romney backs challenger in Michigan MORE (R) in his primary against Rep. Kerry BentivolioKerry BentivolioIndiana Republican: Leaders duped me Reindeer farmer saves 'cromnibus' with yes vote High drama as .1T spending package advances by one vote MORE (R-Mich.), the latest big-name Republican to weigh in on Trott's behalf.

"As someone who grew up in Michigan and has family currently living in the 11th District, I am confident that Dave Trott has the honesty, integrity and experience we need in Washington," Romney said in a statement released by Trott's campaign. "As a job-creator, Dave Trott knows how to balance budgets, cut spending, and fix the mess in Washington.  I am proud to endorse Dave Trott for Congress."

Trott has been pulling in huge sums for the race against Bentivolio, who won his seat after then-Rep. Thad McCotter (R-Mich.) failed to qualify for the ballot, and a write-in campaign organized by establishment Republicans fizzled against him.

Bentivolio's campaign is in shambles, and Trott is likely the favorite to win this primary.