House Democratic leaders received no warning before conservative Rep. Ralph Hall (D-Texas) defected from the minority party last week, but no one was surprised by the move, sources throughout the Caucus said Monday.

Hall, a long time friend of President Bush’s who rarely votes with the Democrats, declared his intent to switch parties Friday when he filed for re-election as a Republican. He was expected to formally resign from the Democratic Caucus as early as today, Democratic leadership sources said.

“I’m not aware that Mr. Hall gave the Democratic leadership any advance notice, nor did we expect to receive such a notice,” said one leadership aide. “It goes without saying that we expected he would eventually — when it was politically convenient for him — to make such a move.”

Minority Leader Nancy Pelosi (D-Calif.) and Minority Whip Steny Hoyer (D-Md.), who is traveling in India, declined comment Monday on Hall’s switch.

Republican leaders, meanwhile, issued statements praising Hall’s decision and pointed out that the Texas lawmaker had already amassed a conservative voting record before the switch.

Speaker Dennis Hastert (R-Ill.) called Hall “a man of great courage and a man of great distinction,” while National Republican Congressional Committee Chairman Tom Reynolds (N.Y.) also referenced Hall’s “courage.”

“I think I can speak for the Republican Conference in saying that we welcome Ralph Hall with open arms,” said Reynolds, emphasizing the lawmaker’s close relationship with Bush.

A major play now begins for the Texan’s seat on the Energy and Commerce Committee, a powerful and highly sought-after panel. Pressure and lobbying will be intense on Pelosi and the Steering and Policy Committee as they select a replacement, leadership sources said.

Some possibilities to take the seat include members of the Texas delegation; conservative Reps. Dennis Moore (Kan.) and Jim Matheson (Utah), who sit in swing districts; or Rep. Tammy Baldwin (Wis.), a progressive Member from a more secure district.

Meanwhile, Pelosi wasted no time Monday filling Hall’s ranking seat on the Science Committee. She quickly tapped Rep. Bart Gordon (D-Tenn.), next in line in seniority, to take the top Democratic slot on that panel.

Hall said he switched because as a member of the GOP he could get re-elected more easily and do more for his constituents. The move also comes as Texas awaits a final ruling on its highly controversial redistricting map, which could hurt several House Democrats’ chances for re-election.

Members throughout the Caucus remained largely unaffected by the defection, saying while it’s not good news, Hall was never a team player and rarely sided with Democrats on votes. For example, Hall voted “present” rather than support Pelosi in her symbolic bid for Speaker last year.

“The bottom line is it doesn’t really matter,” one well-placed Democratic aide said of the Hall move. “He didn’t vote with us. As far as I’m concerned it will free up space on Commerce.”

Democratic leadership sources indicated the Steering Committee will look to fill the space soon, perhaps before Congress returns Jan. 20 or shortly thereafter.

Following the move, Democrats now need to capture an additional 13 seats in order to wrest control away from the GOP. They began the 108th Congress with 205 seats.