Presidential campaigns ideally are about real differences. Here on a perfect summer day before a crowd of nearly 300 in the Town Hall, Republican candidate John McCain did what a presidential candidate is supposed to do. He told his audience why he is running for president.

He spoke forcefully and clearly about differences between him and everybody else running in both parties. With controlled passion, he indicted the existing campaign finance system, which officeholders in both parties -- but especially in McCain's GOP -- have mastered to their own enormous personal and political advantage.

The mostly Republican crowd interrupted McCain 16 times with applause and cheers, as the senator placed the blame for "widespread cynicism" on "those of us privileged to hold public office . . . who have squandered the public trust. We who have time and again placed our personal and partisan interests before the national interest."

But this was more than predictable moral outrage. In July McCain tried to force Senate action on the campaign finance reform bill he and Wisconsin Democrat Russ Feingold wrote to ban "soft money," the unlimited and unregulated six-figure gifts from organized labor, international business and very wealthy individuals. He told the New Hampshire crowd how "every company affected by [the 1996 Telecommunications Act] had purchased a seat at the table with soft money."

The Arizona conservative added that ordinary voters "had no seat at the table." The communications companies got what they paid for, he reported: "Cable rates went up. Phone rates went up, and huge broadcasting giants received for free billions of dollars in digital spectrum, property that belonged to the American people."

There is nothing abstract about cable rates and monthly telephone bills. McCain reminded primary voters in attendance that under Bill Clinton, "The Lincoln Bedroom has become a Motel 6 where the president of the United States serves as the bellhop."

Wasteful federal spending won't end, and education, health care and the tax system won't be reformed until the existing order is overturned. You cannot change Washington or change America until you change the way campaigns and candidates are paid for and bought by big rollers. That's the McCain premise: "We won't reform anything until we first reform the way we finance our political campaigns."

The reaction in Bedford was positive. Barbara Stone, a former town Republican chairman, declared herself "very impressed. I'm signing up right now." Linda Johnson of Bedford believes McCain has "more depth, more character and more experience than Bush." That would be George W., the front-running Texas governor, the $36 million man who has failed to match the boldness of his father, the former president, who has championed the abolition of soft money.

John McCain, a flawed man, has put political money and its influence on the national agenda, to the discomfort of his colleagues. This is no tactical ploy. He believes in what he's doing.

John McCain's courage and honor have been tested before -- as pilot and POW in the Vietnam War -- by adversaries perhaps more savage but none more slippery than those he knows he now faces. Then he was not found wanting. Now he has earned his nation's gratitude -- again.