WASHINGTON —  The Senate will pass campaign finance legislation by week's end even if lawmakers must work around the clock to overcome opponents' stalling tactics, Senate Majority Leader Tom Daschle said Sunday.

"I believe we will get it done, either the easy way or the hard way, but it will be done by Friday," said Daschle, D-S.D.

A final vote on the bill, which would bring about the most significant changes in a quarter-century in how campaigns are financed, could come as early as Wednesday. Passage would send it to President Bush, who has indicated he would sign it.

The bill, introduced by Sens. John McCain, R-Ariz., and Russ Feingold, D-Wis., bans the hundreds of millions of dollars that corporations, unions and individuals give to the national political parties in unregulated "soft money." It also restricts in the final days before an election the "issue ads" that often indirectly attack candidates.

"I see $500 million taken out of American political campaigns immediately by doing away with soft money," McCain said on Fox News Sunday. "I think you'll see, for those of us that are growing old, a return to the time of the 1980s when we had to have party organizations, volunteers knock on doors."

Republican opponents, who say the restrictions on contributions violate First Amendment free speech rights, acknowledge that they are in the minority. But even if supporters gain the 60 votes needed to limit debate, Senate rules provide opponents with 30 hours to debate the measure.

Daschle has threatened to hold the Senate in all-night sessions if necessary to use up the time available to opponents intent on filibustering.

"We expect right now that there will be a filibuster, which is why I brought the cots in last week," Daschle said on CBS' Face the Nation.

The Senate's No. 2 Republican, Oklahoma's Don Nickles, said he thought the legislation would pass quickly, and without amendments.

"I think some of the opponents of it have exaggerated how bad it is, and I think some of the proponents have overexaggerated," he said on Fox.