Ralph is a man I admire and someone to whom I also happen to owe a measure of personal gratitude. More than two years ago -- back before he decided retrospectively to become a supporter of impeachment, when he was among the most trenchant and thoughtful critics of Kenneth Starr -- Nader supported the research for "The Hunting of the President," the book I coauthored with Gene Lyons. That is among the many reasons I am sorry to say I think his presidential campaign is attempting to mislead voters, the consumers of democracy.

The premises of Nader's campaign, which threatens to deliver certain key states to the Republicans in November, are that the two major parties have become so similar that it doesn't matter which one wins the White House; and that through his candidacy, the Green Party will become a viable institution to advance progressive goals. Neither of those selling points is consistent with truth in advertising.

As one of the nation's premier intellectuals concerned with federal policy, with particular expertise in matters where Democrats and Republicans are indeed very different, it is hard to imagine that Nader really believes his own rhetoric about "Republicrats." For an advocate such as him -- whose life's work is based on the idea that government has a responsibility to protect consumers, workers and families from corporate depredation -- the distinction between the major parties could never have appeared as stark as it does now.

Today's Republican Party is an entirely corporate-dominated entity whose congressional leaders are utterly hostile to the environmental, consumer and workplace safety agencies that Nader played an important role in creating. For all their imperfections and compromises, and their increasing reliance on corporate soft money, the Democrats maintain their traditional support for all those essential institutions. Many of them have been reinvigorated under the Clinton presidency, after more than a decade of stagnation, influence-peddling and outright corruption during the Reagan and Bush administrations.

The memories of Nader's supporters may be too short to recall the fate of the Environmental Protection Agency, the Occupational Safety and Health Administration, the Federal Trade Commission, and all the other federal offices that were crippled under Reagan and Bush. But somehow I suspect that Ralph is only pretending amnesia. Does he really think the lobbyists and executives who have raised $100 million to elect George W. Bush are full of benign intentions? Isn't it obvious that this time around, especially if the Republicans also maintain control of Congress, this crowd will try to finish the wrecking job they began in the 1980s?

Even on the issue of global trade, Democrats at least acknowledge that globalization shouldn't sacrifice environmental and labor standards for the sake of commerce. Republican ideology places no value whatsoever on those concerns, which are regarded by GOP ideologues only as potential impediments to the marvels of the marketplace.

The list of issues that distinguish Democrats from Republicans is long and indisputable. It begins with the minimum wage, which Democrats have consistently raised and Republicans would prefer to see abolished, and goes on through reproductive rights, affirmative action, gay and minority rights, to the regulation of rapacious health insurers and the maintenance of the freedom to sue corporate wrongdoers (a special concern of Nader's). For upper-middle-class liberals -- to whom all these questions are comfortably abstract -- a vanity vote for Nader may well be an affordable luxury. For everyone else, that choice represents a flirtation with disaster.

The argument that the major parties are identical is absurd, but even less plausible is the notion that the Green Party will ever become a useful alternative. Third parties that claim they are on the way to displacing the Democrats or the Republicans are invariably perpetrating a consumer fraud.

More than a century has passed since such a party ascended into real electoral competition; in recent times, all of the rump parties have been spoilers. When they aren't spoilers, they simply spoil away themselves into factional isolation and irrelevance. That is what happened with the Citizens Party in 1980, the precursor of today's Green Party. It is also what happened to the movement around John Anderson's candidacy that same year, which failed so pitifully that it couldn't even take a share of the blame for electing Reagan.

More immediately, that kind of political decay is what is happening right now to the Reform Party, an effort with better funding and a more significant social base than the Greens will ever possess. Well-meaning and sincere as they are, the Greens call to mind George Orwell's acid description of the fringe personalities and obsessions that once made British socialism unattractive to ordinary people.

In this country, the same small-party patent medicine has been peddled by the same few figures on the far left for more than two decades. It is about as useful for curing cancer or growing hair as it has been in reforming American politics. Ralph Nader shouldn't be lending his illustrious name to a fake like this. And it is sad that to whatever extent he does succeed this fall, he will only be undermining the extraordinary public contributions of his own lifetime.

Politics 2000: Unflinching daily political news, analysis and commentary.