JACKSON (AP) — Conservative Democrat Travis Childers won a north Mississippi congressional runoff Tuesday in a race the Republican Party tried to cast as a referendum on Barack Obama and the national Democratic Party.

It was the third U.S. House seat this year that Democrats have taken over from Republicans in special elections.

Childers defeated Republican Greg Davis in a runoff and will fill the last several months of a two-year term the GOP’s Roger Wicker started in January 2007. Wicker had served in the House since 1994.

Republican Gov. Haley Barbour appointed Wicker to the U.S. Senate in December after Trent Lott retired.

With 100 percent of precincts reporting, Childers had 57,275 votes, or 54 percent, and Davis had 49,314 votes, or 46 percent.

Just before speaking to supporters at his victory party in Booneville, Childers told The Associated Press he believes the negative tone of the campaign was “a sad state of affairs,” and said he takes responsibility for his part.

“It does not speak well for us as a society when politics gets to that level,” said Childers, the 50-year-old chancery clerk in northeast Mississippi’s Prentiss County.

Davis, the 42-year-old mayor of Southaven, could not immediately be reached.

In Louisiana on May 3, Democrat Don Cazayoux won a special election May 3, taking a seat Republicans had held since 1974. In Illinois in March, Democrat Bill Foster won a special election in the district long represented by Republican former Speaker Dennis Hastert.

Democrats now hold a 236-199 majority in the House.

Marty Wiseman, a political scientist at Mississippi State University, said if Democrats can carry districts that should’ve been safe bets for the GOP, “Republican strategists have to be terrified.”

“If you think about the House and the Senate … and the number of Republican Senate seats that are exposed, this could turn into something bigger than the presidential race this fall,” Wiseman said Tuesday night.

Tom Cole, chairman of the National Republican Congressional Committee, said the loss in Mississippi shows that “Republicans must be prepared to campaign against Democrat challengers who are running as conservatives, even as they try to join a liberal Democrat majority.”

Cole said in a news release that voters are “pessimistic about the direction of the country and the Republican Party in general” and the GOP must offer “positive change.”

Childers racked up votes in the eastern and rural parts of the district Tuesday, while Davis ran strong in his own home base of DeSoto County, just south of Memphis, Tenn.

Davis tried to cast the election in 24 counties as a referendum on the national Democratic Party by saying Childers would be beholden to House Speaker Nancy Pelosi and presidential candidate Barack Obama.

Davis said recently that the runoff election gave voters a chance to show “what team their congressman from the 1st District is going to be on.”

Childers has spoken against abortion and for gun owners’ rights — positions that are nearly identical to his opponent’s.

“They always wanted that to be a national race,” Childers said Tuesday, speaking of the Republicans. “I still think it’s a local race. I still think it’s about the 24 counties of north Mississippi.”

Obama and Pelosi issued news releases congratulating Childers.

“By electing Travis in this traditionally overwhelmingly Republican district, the people of Mississippi voted to end the politics of division and distraction, and bring about real change,” Obama said.

Pelosi said: “Travis Childers earned the votes of the people of Mississippi’s 1st Congressional District because he reflects their values and shares their hopes and dreams for the future.”

About 700 people turned out Monday in Southaven to hear Vice President Dick Cheney campaign for Davis. Barbour and Republican Lt. Gov. Phil Bryant also campaigned for Davis in the district.

Mississippi’s 1st District, with about a 75 percent white voting-age population, stretches from the Delta flatlands on its western edge to the Appalachian foothills in the northeast. The area’s furniture manufacturing industry has eroded over the past two decades, but a new Toyota plant is being built near Tupelo.

Childers and Davis advanced to Tuesday’s runoff by grabbing the top two spots in a six-person special election April 22. Childers got 49 percent to Davis’ 46 percent then.

Childers, Davis and two other candidates will be on the Nov. 4 general election ballot to seek a two-year term that starts next January. The winner of Tuesday’s runoff will be the incumbent with a likely advantage in fundraising and name recognition.

Childers has signed a pledge not to approve any international trade agreements if he’s elected, saying that deals such as NAFTA have made jobs disappear. Davis has signed a pledge not to increase taxes.