Republican Ex-U.S. attorney will file for Senate in Iowa this week

Whitaker, a former football star at the University of Iowa, said he'd seek to emulate Sens. Rand Paul (R-Ky.) and Ted Cruz (R-Texas) if elected and could draw some strong support from Tea Party and libertarian voters in the primary. But those views could be tough to sell statewide in the swing state.

A number of Republicans, including the state's governor, lieutenant governor, both Republican House members and the state's agriculture secretary have previously ruled out a challenge to Rep. Bruce Braley (D-Iowa) for the seat being vacated by Sen. Tom Harkin's (D-Iowa) retirement.

Other potential GOP candidates include Secretary of State Matt Schultz (R), Iowa state Sen. Joni Ernst (R) and Sen. Charles Grassley's (R-Iowa) chief of staff, David Young.

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