The Senate on Thursday all but buried campaign finance overhaul efforts for at least another year.

Despite a yearlong investigation into the abuse-plagued election of 1996 and sometimes sensational hearings into the lengths that President Clinton's re-election campaign went to raise money, the advocates of revising the campaign finance law could not, in the end, expand their coalition to triumph over a Republican filibuster.Instead, in successive votes of 51-48 and 45-54 Thursday, the Senate first failed to end debate on the main bipartisan overhaul bill and then on a competing proposal by Republican majority leader Trent Lott aimed only at organized labor. It takes 60 votes to cut off Senate debate and force a vote on legislation.

With the Senate at a stalemate, Lott, a primary foe of the overhaul effort, removed both bills from the floor to clear the way for popular pork-barrel legislation to allot transportation projects to the states. Having cycled through familiar debate all week, no one objected.

Sen. John McCain, R-Ariz., one of the major architects of the bill to overhaul the campaign finance law, promised to battle again another time. "We will not quit, and we will prevail," McCain said after the vote, standing on the lawn of the Capitol with his closest allies.

But the group was under no illusions. When Sen. Joseph Lieberman, D-Conn., mentioned some smaller steps that might be taken, like reinforcing prohibitions against fund-raising in public buildings, and then asked, "Who is going to be against that?" Sen. Susan Collins, R-Maine, muttered, "You'd be surprised."

Democrats, who provided most of the support for the bill, held open the possibility that they might fight on later this year. And the House has its own debate ahead late next month.

But for all practical purposes, campaign finance overhaul now moves from the legislative to the political arena as an issue in the midterm elections.

House minority leader Dick Gephardt immediately made clear that Democrats would showcase Republican opposition to the bill, which was co-sponsored by McCain and Sen. Russell Feingold, D-Wis.

The debate, Gephardt said, showed "which party is really for campaign reform and which party is not."

Gov. Roy Romer of Colorado, the general chairman of the Democratic National Committee, predicted that his party would wield the issue against two Republican senators in particular - Alfonse D'Amato of New York and Christopher Bond of Missouri.

But Sen. Mitch McConnell, R-Ky., chairman of the Senate Republicans' campaign committee, said, "No one in the history of American politics has ever won or lost a campaign on the subject of campaign finance reform."

McConnell said three groups that provide valuable grass-roots support to Republican candidates - the National Rifle Association, the Christian Coalition and the National Right to Life Committee - had strongly opposed the McCain-Feingold measure. The groups maintain that the overhaul legislation would hamper their ability to spread their political message. The National Right to Life Committee has already mounted a radio campaign against Feingold.