CQ Politics, 3/10/8

While national attention is focused on Tuesday’s stand-alone primary showdown in Mississippi between Democratic presidential contenders Barack Obama and Hillary Rodham Clinton , there also are congressional primaries that will have an even more immediate impact on the state’s two key U.S. House races.

Voters in the 1st and 3rd Congressional Districts will participate in pivotal contests. The 1st currently is vacant because incumbent Republican Roger Wicker was appointed to the U.S. Senate, and the 3rd is open because Republican Rep. Charles W. “Chip” Pickering Jr. is retiring.

Both districts have strongly conservative electorates and definite Republican leans, making Tuesday’s GOP primary winners all-but-certain new faces in Congress.