It's hard to believe, I know, but there is now an entire generation of 20- and 30-something Americans who don't know that Ralph Nader wasn't always a total a**hole. And yet, despite the stupefying narcissism and destructive potential of Nader's 2008 presidential bid, there's one important issue raised by his independent race that a legitimate fear of his candidacy's consequences, or a well-earned contempt for his arrogance, should not be allowed to obscure.

By now we are used to politicians and public figures who use the presidential campaign cycle to build equity and raise fees for their Brand That Is Me (Al Sharpton, Alan Keyes, Rudy Giuliani); to act out their messianic delusions on a national stage (Ross Perot, Mike Gravel, Fred Thompson); to audition for the demagogic hall of fame (Tom Tancredo, Duncan Hunter, and an asterisk for Lou Dobbs, who still seems to be flirting with it).

Nader, of course, says he's different. (He also says that he didn't cost Al Gore the 2000 election -- "this bit about 'spoiler' is really very astonishing," he told Tim Russert -- which puts something of a ceiling on the credibility of anything else he says.) Nader contends that the good he did in that race was to pull Gore's positions to the left. It's a role that John Edwards (though not Dennis Kucinich -- go figure) is credited for playing in the 2008 primaries. And now Nader, who skipped the primaries, says that his third-party race will inject into the fall campaign issues like single-payer health insurance, labor law reform, Pentagon waste, corporate crime, "the illegal occupation of Palestine," and impeachment -- issues he says Clinton, Obama, and McCain have taken off the table.

I don't doubt that there's a portion of the American electorate that agrees more with Nader on some of those issues than they do with anyone the Republicans or Democrats will put on the ballot. Hell, I'm one of them. Just to pick one topic: I think the unwillingness of the Congress to hold Bush and Cheney accountable for carpet-bombing our system of checks and balances, and for replacing the rule of law with the tyranny of despots, has not only been a craven capitulation to White House fear-mongering; it has also staggeringly misread the political mood and core values of the American people. And I hold Clinton, Obama (and even McCain 1.0, the maverick), along with their colleagues, responsible for sweeping the ashes of our Constitution under the rug.

But despite Nader's wishful thinking, we don't have a parliamentary system. Any votes he attracts will be drained from the Democratic nominee and conceivably cost an Electoral College victory; they will not result in a new government being forced to enter into a coalition with his supporters. Nor, I think, will his presence in the race reframe the issues, refocus the choices, or push the envelope of the campaign. Even though I may agree with him on, say, single-payer, I could live with criteria for getting into a fall presidential debate that turned out to exclude him.

What troubles me, though, and what his bid throws a spotlight on, is how hard it is for anyone in America to shape the national conversation on anything. One way or another, it takes big money -- the fortune to run for office, the cash to buy full-page ads in newspapers, the bankroll to own a network, the marketing budget to create a celebrity's star power. Markets move mass media. In the internet age, almost any idea can find an audience somewhere, but to win MSM airplay and a seat at the table, that audience's numbers have to be big enough to constitute a politically potent special interest or infotainment freakshow fan club, not just a narrowcast alternative niche or a responsibly dissenting viewpoint.

It's a shame that to get five minutes of the nation's civic attention, a person has to either be a billionaire, or to raise and spend a billion of other people's dollars, or to do something as potentially lethal the country's ultimate well-being as to mount a quixotic run for president. Maybe we already possess the communications technology for a modern-day Tom Paine to reframe the national political debate without at the same time landing another George W. Bush in the White House. The irony is that the candidate most likely to focus on the barriers to success standing in the way of that technology -- the concentrated, corporate control of the media -- is the same Ralph Nader whose presence in the race may turn out to cast the darkest shadow on its outcome.