WASHINGTON — Another top Georgia Democrat will announce today that he's backing Sen. Barack Obama in the Democrat presidential race.

Rep. John Barrow of Savannah, who represents a toss-up district and who had one of the toughest re-elections battles in the country in 2006, picked Obama over Sen. Hillary Clinton, saying Obama's already proven his willingness and ability to work in a bipartisan manner.

"He's the one who has shown in his work that he's able to work with all sides," Barrow said.

Obama now has the backing of all five of the Democratic congressmen from Georgia who have announced a preference. Clinton now has no public support from the state's congressional super delegates to the Democratic national convention this summer.

Barrow said Obama's bipartisanship more than makes up for his relatively short experience in Washington.

"The best indicator of what a person's going to do in the future is what they've done in the past," he said.

Barrows' announcement comes a day after Rep. John Lewis, an Atlanta Democrat, announced that he's switching his support from Clinton to Obama.

Unlike Lewis, however, Barrow had not endorsed anyone in the Democrat primary until now. He said he cast his primary ballot earlier this month for Obama, "but felt I owed to everybody to pay attention to how everyone else (in his district) voted" prior to making a public announcement.

Democratic Rep. Jim Marshall of Macon, whose district is divided even more closely between the parties than Barrow's, is the only Georgia congressman who has not announced a preference in his party's presidential race.

Other superdelegates remain uncommitted, including party chairwoman Jane Kidd and former President Jimmy Carter, both of whom have said they'll remain neutral.

The other two are Democratic National Committee members Mary Long and Richard Ray. Both said Thursday that Lewis' decision would have no influence on theirs.

"I still hae not made any decision," Long said. "The people are going back and forth and back and forth."

It's different, she said, for Lewis and other elected officials. "It's a different fear," she said, of having to follow their constituents.

Ray agreed. Of Lewis, he said, "I appreciate what he did, knowing he has a lot of pressure. But he is in a little different position than I am."

Staff writer Aaron Gould Sheinin contributed to this report.