ATLANTA --- The chairman of the Republican Senatorial Campaign Committee says Sen. Saxby Chambliss will be a key part of the firewall the party wants to build against stronger Democratic control of Congress.

Sen. John Ensign, R-Nev., set a floor on the number of Senate seats the party must control: 41.

"The number that we get to is really, really important in the U.S. Senate," he said. "That's one of the reasons Saxby absolutely must hold his seat."

Democrats now have 49 seats with two independents who vote with them. Republicans hold 49, with 23 up for re-election this year, and five GOP senators retiring. Democrats only have to defend 12 seats this year.

By holding at least 41 Senate seats, the GOP would prevent the Democrats from having the 60 votes required to end filibusters, which prevent votes on bills.

Mr. Chambliss said last week that he expects a tough contest no matter who the Democrats run against him.