JACKSON, Miss. — Travis Childers, a conservative Democrat who served just over two years in Congress before being defeated as Republicans grabbed the House majority in 2010, said Friday that he's running for the U.S. Senate in Mississippi this year.

Childers told The Associated Press in a phone interview that he has qualified for seat that Republican Thad Cochran first won in 1978. Cochran is being challenged by two-term state Sen. Chris McDaniel in the Republican primary.

Childers won north Mississippi's 1st District U.S. House seat in a mid-2008 special election. He won a full two-year term that November, then was defeated in 2010 by a Republican who painted Childers as an ally of Nancy Pelosi, the California Democrat who was then speaker of the House. Childers bristled at the portrayal, noting that he had voted against Pelosi on big bills, including the health overhaul that President Barack Obama signed into law in 2010.

Childers told AP last November, before Cochran announced for re-election, that he worked well with Cochran in Washington. Childers said then that he preferred not to run for Senate if Cochran were running again. On Friday, Childers said that if he wins the Democratic nomination, he will remain in the race even if Cochran wins the GOP nomination.

"I've never been in a race that I didn't run to win," Childers, 55, said Friday.

Childers' decision to run gives Democrats an experienced candidate with name recognition. The last Democrat to serve in the Senate from Mississippi was John C. Stennis, who retired in early 1989 after nearly 52 years in office. Seven of Mississippi's eight current statewide elected officials, from governor to insurance commissioner, are Republican. The state has voted Republican in every presidential election since 1980.

In the Democratic primary, Childers will face Bill Marcy, who has twice run unsuccessfully for Mississippi's 2nd District U.S. House seat as a tea party Republican.

Candidates' qualifying deadline is Saturday, and party primaries are June 3.

Although Democrats have had difficulty winning statewide elections in Mississippi, the state has a 37 percent black population and Democrats generally fare well in majority-black counties.

U.S. Rep. Bennie Thompson, a Democrat who's the only black member of Mississippi's current congressional delegation, said Friday that he can see a scenario for a Democrat to win a Senate race if Cochran loses the Republican primary.

"A lot depends on how aggressive Sen. Cochran is in his campaign before the primary," Thompson said.

Childers was chancery clerk in north Mississippi's Prentiss County more than 16 years before going to the U.S. House. That job helped him make contacts in county courthouses across the state, an important element in building a political network.

Marcy has lost twice to Thompson. Marcy, who is black, said in January that if he wins the Democratic nomination for Senate, he wants to build a general-election coalition of black voters and tea party voters. That's a doubtful scenario, given Mississippi's political history.