ASHINGTON - Senator John McCain's voice could barely be heard. ''So, we lost,'' the former Republican presidential candidate said quietly on the phone from the Phoenix airport, after learning that the House yesterday had defeated his latest campaign finance proposal.
It was a fast reversal: Just 17 hours earlier, McCain had shocked Senate Republican leaders by winning approval of a measure that would require disclosure of the donors who contribute to a secretive new class of political organizations. But the House yesterday voted 216-202 against the measure, with only six Republicans joining Democrats in support.
The short-lived nature of McCain's victory shows that one of the most talked-about issues of the primaries - overhauling the way campaigns are financed - has yet to sweep through both houses of Congress.
The vote also underscored how far McCain still has to go before attaining his ultimate and more difficult goal, banning the unregulated ''soft money'' used by both political parties.
McCain said he still hopes the disclosure measure will be approved this summer, but acknowledged that a vote to ban soft money is unlikely until after the election. Indeed, the odds are still strongly against a soft money ban any time soon. The chief advocate, McCain, was defeated in the primaries by George W. Bush, who wants to keep soft money legal.
And while Vice President Al Gore favors a soft money ban, his election would not ensure its enactment. He probably would still face difficulty getting a veto-proof majority for the proposal in Congress.
''I can't tell you that all of a sudden we will have a magic breakthrough, a win,'' McCain said. But Thursday's Senate vote was ''the first time since 1993 on any kind of win on campaign finance. It was a seminal moment in the reform movement.''
Yesterday's House vote was on a relatively narrow question: whether to require a new class of political organizations, known as ''527s'' under the tax code, to disclose the names of their donors. A 527 organization called ''Republicans for Clean Air'' and funded by two Bush supporters ran a $2 million campaign against McCain during the New York primary. They accused the Arizonan of anti-environmental votes.
Bush yesterday said he supported the idea of requiring the disclosure of 527 donors.
These groups span a range of political viewpoints. One of the best-known is the Sierra Club, an environmental group.
Recently, a group called Shape the Debate, with a reported $1.5 million bankroll, began running anti-Gore ads that borrow the format of the ''Jeopardy'' quiz show, with contestants in a ''Hypocrisy'' game asked to identify various actions by Gore. The organization is run by associates of former governor Pete Wilson, a California Republican, and it includes political consultant George Gorton.
The organization's Internet Web site (www.shapethedebate.com) makes clear why 527s have become politically attractive. It notes that unlike the publicly disclosed and limited $1,000-per-person contributions to a political campaign, donations to Shape the Debate have no limitations. The Web site tells potential donors that contributions ''can be given in unlimited amounts, can be from any source (and) are not political contributions, and are not a matter of public record.''
Nothing in the 527 legislation would have prevented such organizations from continuing to spend unlimited amounts of money, which many critics have said is the main problem with the groups. But McCain said disclosure of the donors is an important first step. Moreover, McCain said he had support in both the Senate and the House for the measure because some of the vociferous opponents of campaign-finance overhaul have said problems with the system can be solved by requiring full disclosure.
But House Republican leaders objected to the proposal, partly because it would affect a 527 organization run by House majority whip Tom DeLay of Texas. During the floor debate yesterday, GOP leaders said they were concerned some organizations that donate mostly to Democrats, such as labor unions, would not be affected by the disclosure legislation. Republicans have long argued that any campaign-finance measure must enable union members to withhold dues that go toward political ads.
Republican leaders said they would come up with a new proposal to be voted on before the July 4 break.
''This is not about political vendettas or partisan politics,'' said House majority leader Dick Armey of Texas, who led the opposition to the disclosure measure. ''It is about the key principle of full and fair disclosure for all institutions that engage in political advocacy.''
But some Republicans said there was no justification for allowing the names of donors to be secret.
''These tax-exempt 527s could be the communist Chinese, drug lords, the Mafia, who knows?'' said Representative Greg Ganske, the Iowa Republican.
Representative Martin Meehan, a Lowell Democrat who has cosponsored a measure to ban soft money, said it is imperative to require disclosure of 527 donors immediately because the groups are secretly gathering millions of dollars in preparation for the fall campaign.
''The 527s are flagrant abuse, even worse than soft money, because no one has any idea where the millions of dollars are coming from,'' Meehan said.
