Senate Democrats on Monday blocked an immediate vote on a call by one of their own to censure President Bush for his eavesdropping program.

They acted after Republicans said they were eager to pass judgment on a proposal that they portrayed as baseless and disruptive to the antiterror effort.

Minutes before Senator Russell D. Feingold, Democrat of Wisconsin, formally introduced his resolution reprimanding Mr. Bush, Senator Bill Frist of Tennessee, the majority leader, said Republicans were ready to vote by day's end or Tuesday...

Democrats, while distancing themselves from Mr. Feingold's assertion that the president "plainly broke the law" in approving surveillance without warrants, said his proposal merited more consideration than a hasty vote.

"To try to limit debate on this most important matter that Senator Feingold is going to put before the Senate is not appropriate," said Senator Harry Reid of Nevada, the minority leader.