Rep. Tom Latham (R-Iowa) announced Friday that he will move to Iowa's 3rd Congressional District ahead of next year and take on eight-term incumbent Leonard Boswell (D-Iowa) rather than face a primary with fellow Republican Rep. Steve King.

Latham's decision comes after state lawmakers in Iowa approved a new map Thursday that puts Latham and King in the same congressional district for 2012. The two Republicans were anxious to avoid a primary fight in 2012, and the party sees a Latham-Boswell race as winnable for the GOP. 

Republican Gov. Terry Branstad announced Friday that he will sign the redistricting plan into law. 

"I have never let map boundaries block the great honor I have felt in representing the interests of all Iowans in the United States Congress," Latham said in a statement Friday.

Boswell, meanwhile, told The Ballot Box earlier this week that he's ready for a matchup with Latham, promising the Republican a tough race.

"I live in Polk County, in the capital city," Boswell said. "That's my base, and whatever gets attached to it, so be it. But I'm not going anywhere."

The longtime Democrat, who survived a contested race in 2010, said he's been conditioned to expect a tough battle every year, adding that his new district will have "half the counties I've served before anyway."

The National Republican Congressional Committee praised Latham in a statement Friday as "a proven conservative leader" and pledged support in his race against Boswell. 

“The NRCC is committed to re-electing every House Republican Member through our Patriot Program, which empowers House Republicans with the strategies and resources to stay on offense against Nancy Pelosi’s House Democrats," NRCC Chairman Pete Sessions (Texas) said in a statement. "We look forward to supporting Tom Latham as he takes on a new opportunity for Republican victory in 2012.”

Latham's decision leaves the new 4th District to King for 2012.

"Having represented nearly half of the new Fourth District since 2002, I look forward to continuing to represent the interests of northwest Iowa in Congress, and I am looking forward to building new relationships in new communities across north central Iowa," King said in a statement Friday.

Of Latham, he said, "I am pleased that the residents of the southern part of my current district will have the opportunity to choose Tom Latham as their representative in Congress.

-Updated at 12:35 p.m.