The Senate yesterday refused for a second time to stop a Republican filibuster blocking action on a political campaign-revision bill that includes limits on spending by Senate candidates and provides federal financing of elections.

A third attempt to end the filibuster was set for today and a fourth for Thursday. Senate Majority Leader Robert C. Byrd (D-W.Va.) said "no delay or obstruction" by Republicans will move him to abandon the bill, a showcase priority for Democrats since the start of the 100th Congress in January.

The Senate, sticking almost strictly to party lines, voted 49 to 46 to cut off debate, 11 short of the required 60. On the first attempt, last week, the vote was 52 to 47.

The blocked legislation would provide partial federal financing for Senate candidates in return for fixed state-by-state limits on candidate spending.

Democrats revamped their original bill to cut by more than half the amount candidates could draw from the U.S. Treasury. Republicans, however, rejected the new offer.

Senate Minority Leader Robert J. Dole (R-Kan.), Sen. David L. Boren (D-Okla.), the main sponsor of the bill, and Byrd said they were willing to negotiate a compromise but the parties appeared no nearer a consensus than they were last week.

Despite the lack of movement, Boren said Byrd told him earlier in the day "no delay or obstruction is going to keep him from getting it up -- will keep coming up. He told me this is an issue that is not going to go away."