You don't have to believe every stockbroker is an embezzler to support securities laws that prevent fraud when you buy shares in a company. And you can support campaign finance reform without believing every member of Congress is a corrupt human vending machine selling every vote on every issue to the largest campaign contributor.

It's enough to believe the evidence that big campaign contributors have too much influence on Washington, that lobbyists bearing large gifts have amassed too much power and that much public cynicism is rooted in a realistic sense that, too often, money rules.

That's why campaign reform keeps edging toward victory, and one reason why Sen. John McCain (R-Ariz.), a tribune of fixing the system, is emerging as the most plausible challenger to Texas Gov. George W. Bush for the Republican presidential nomination.

In the simple sense, reformers lost again this week in the Senate. They couldn't muster the 60 votes needed to break the filibuster that thwarts the pro-reform majority. But three more Republicans--Sens. Sam Brownback of Kansas, Tim Hutchinson of Arkansas and Bill Roth of Delaware--brought the reformers ranks to 55 by casting their lot with those trying to ban "soft money." That's the cash businesses, unions and individuals can toss at political parties in unlimited amounts.

At the edges, Sen. Chuck Hagel, a Nebraska Republican, floats intriguing if problematic compromises. His activities suggest that the once-solid front against reform built by Sen. Mitch McConnell (R-Ky.) is weakening.

You can tell reform foes are worried by their increasingly shrill arguments, whose undertone is that any limits on money's writ could transform the country into a totalitarian state. Arguments along those lines would certainly surprise a Republican named Theodore Roosevelt. As president, he supported an end to direct corporate contributions to politics. That ban, passed in 1907, had no apparent ill effects on our admirable national habit of exercising free speech rights boisterously.

But give McConnell this: Like a good lawyer, he grabs any argument available to achieve his end, and is creative at adjusting to new situations.

To increase support for their bill, McCain and his Democratic reform partner, Sen. Russ Feingold of Wisconsin, decided to drop a provision regulating so-called issue ads.

Part of the reform bill passed by the House earlier this year, the requirement that the sponsors of "issue ads" live by the same rules in the election season as candidates do, should eventually become law. The ads it would regulate are campaign ads in all but name--often quite vicious ones.

This part of the bill, Feingold notes, gave McConnell running room for some of his grander free speech arguments. Once it was gone, McConnell changed course and challenged the whole premise of the reformers: They couldn't claim the system was corrupted, he said, unless they could name the names of corrupt senators or representatives.

"The question is, who is corrupted?" McConnell asked on the Senate floor. "How can there be corruption unless someone is corrupted?"

As a matter of fact, McCain himself was embarrassed this week by a report that his softening of an airline passenger bill of rights just happened to coincide with an infusion of airline industry soft money into the coffers of both parties. McCain denied the money influenced him but acknowledged that "the system tars all of us."

McConnell's question was answered directly by the Supreme Court in its 1976 Buckley decision, which rendered a mixed verdict on the post-Watergate campaign finance law.

"To the extent that large contributions are given to secure a political quid pro quo from current and potential office holders, the integrity of our system of representative democracy is undermined," the court declared. "Although the scope of such pernicious practices can never be reliably ascertained, the deeply disturbing examples surfacing after the 1972 election demonstrate that the problem is not an illusory one."

Exactly: The problem of the money system, with its quid pro quos, is not an invention of the fevered imaginations of reformers.

And so, inch by inch, row by row, the reformers gain ground. That the struggle is taking so long ought not be surprising or disappointing. "What we're doing," McCain told reporters, "is we're asking incumbents to change a system that keeps incumbents in office." That requires time. But McCain hopes Republican primary voters might consider using their ballots to nudge the cause along.