n his valiant effort to turn campaign finance reform into a pivotal issue for the presidential candidates, Senator John McCain of Arizona is traveling a difficult road but one that could prove beneficial to him and the nation.

The central problem is that while a great many Americans share McCain's view that the system is corrupting and needs radical reform, few voters embrace electoral reform as a decisive issue. Most are skeptical that real change will ever occur. They might agree on reform but still vote for someone else.

McCain, a Republican, has a well-earned reputation for challenging the common wisdom. He has recently begun to raise the salience of campaign finance reform by pointing out how it affects individuals.

Telephone bills and other communication costs are higher for consumers, he said recently, because when the Telecommunications Act of 1996 was written, ''every company affected by the legislation had purchased a seat at the table with soft money.'' And special-interest tax breaks soak up money that should go to larger tax cuts for individuals, he said.

This is not a lofty debate about morals but a tough lesson in real costs, and McCain is on the right path.

There have been times when this strategy has worked. After the 1980 Ward Commission report said parts of state government in Massachusetts had essentially been for sale to politicians' cronies and campaign contributors, Michael Dukakis armed his 1982 comeback campaign for governor with an ad about the ''corruption tax.''

''You see,'' said the announcer, ''corruption is the worst kind of tax because you pay and pay and get nothing in return.... The Ward Commission says corrupt politicians have taken billions from Massachusetts taxpayers.'' Dukakis won that election comfortably, helped by an enormous turnout.

McCain said last week he is particularly frustrated that young people ''have figured out that they're no longer represented.'' McCain's theme should give them reason not to lose faith in the American democratic process.