— Veteran Democratic Reps. Brad Sherman and Howard Berman of California are clashing in Los Angeles' San Fernando Valley after new political maps, drawn for the first time by an independent citizens panel, essentially merged their districts. Sherman has said the June 5 primary fight has "adversely affected" their friendship.
— Arizona Rep. Ben Quayle, the son of former Vice President Dan Quayle, is facing fellow GOP freshman Rep. David Schweikert in a Republican-friendly district centered in suburban Phoenix. Quayle has strong party establishment ties while Schweikert has tea party backing.
— Florida veteran Rep. John Mica, who wields Capitol Hill clout as chairman of the House Transportation and Infrastructure Committee, faces a GOP primary showdown with first-term Rep. Sandy Adams, who has tea party backing.
— Missouri Democratic Reps. Russ Carnahan and William Lacy Clay are seeking the St. Louis seat Clay has held for the past 12 years. Carnahan's old district was carved up under a redistricting plan by Missouri's GOP-led state Legislature.
— California Democratic Reps. Janice Hahn and Laura Richardson are vying for a Los Angeles-area seat.
— Michigan Democrats Hansen Clarke and Gary Peters are squaring off in a new district stretching from Detroit to Pontiac.
— Louisiana GOP Reps. Charles Boustany and Jeff Landry were thrown into the same district after redistricting and are expected to square off, though Landry has yet to say whether he will seek re-election.
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