George Carlin, who died last Sunday, wasn’t my favorite comedian, but he uttered an immutable truth when he said that if you scratch a cynic beneath the surface you’ll find a disappointed idealist.

That was never truer – at least about American politics – than it is at the moment. And the reason is Sen. Barack Obama, the self-styled reformer who pledged to bring a new kind of uplifted politics to Washington. Last week, Obama renounced his commitment to public funding now that he’s awash in private cash. And there’s more on the way.

He surrendered his political virginity, you might say, and without much of a fight. Turns out he’s another calculating politician, and, like too many politicians, he puts winning before everything else, even dearly held ideals. Surprise, surprise!

It’s that sort of stuff that turns idealists into cynics.

What makes Obama’s turnabout so unsettling to his editorial page admirers is that, in the catalogue of needed reforms in Washington, nothing is more important than reducing the influence of private money. It’s the ultimate source of corruption in Washington – and city halls and state capitols, too. Nothing would do more to elevate our politics than to rid it of special-interest money. And public funding of federal elections is the way to do it in Washington.

Obama sold out that cause last week. His explanation is that what he’s doing is the next best thing to public funding since his millions have been raised primarily from individual donors, not the fat cats among Washington’s K Street corporate interests. But that statement reeks of hypocrisy because, with Sen. John McCain already committed to public funding of his campaign, this year offered a chance to stage a presidential race on a level financial field – each major party candidate with the same amount of money.

Obama’s switcheroo has put an end to that. Why did he do it? Why risk tarnishing his Boy Scout image and simon-pure appeal to independents?

As I get it, Obama believes he needs a huge cash advantage to, among other things, offset the racial prejudice he faces and the likely infusion of cash from conservative “527” groups, the GOP auxiliaries who “Swift Boated” John Kerry four years ago.

Obama’s money edge will allow him to put staff and television advertising into all 50 states, something never done before in any presidential campaign, and, he hopes, stretch McCain’s money and manpower to the breaking point.

Is it worth traumatizing idealists and independents who have flocked to Obama’s cause? He has slipped a bit with independents recently. Then again, many of them would rather win than lose and will put up with a little hypocrisy to be rid of Republicans in Washington.

The hypocrisy in all this is not limited to the Obama side. No sooner had he thrown public financing under the proverbial bus than the Republican National Committee pounced on him. How dare he, the RNC said in effect, abandon so fine and needed a political reform as public financing? It was a world-class piece of unmitigated chutzpah even for the RNC.

Surely it could not have forgotten how fiercely George W. Bush and the Republican Party have denounced public financing of elections as the devil’s handiwork. The private money advantage in American politics has belonged to the GOP for decades, and so long as it had that edge, it wasn’t going to surrender it. But things are different this year; McCain trails in the money race now.

There’s a lesson here that goes beyond Obama’s sellout of public financing and, indeed, the presidential election, important as it is. It’s that anyone who’s a rabid Republican or die-hard Democrat and wouldn’t consider voting for a candidate of the other party is – how to put it gently? – pathetic. Delusional, for sure.

Neither party truly represents the public interest. Each is at least a semi-captive of a set of vested interests – oil, pharmaceutical and financial corporations on the GOP side; teachers, lawyers and public employee unions on the Democratic side. Indeed, in a larger sense, the two parties are themselves little more than special interests. And neither is worthy of unquestioning loyalty.

Neither party can be counted on to stand for a set of unbendable beliefs. Who would have thought Bush and the “conservative” GOP Congress would prove the most profligate spenders in American history? Or that the “liberal” Bill Clinton would be the presidential vehicle for ending federal welfare?

Makes you see what George Carlin was talking about, doesn’t it?

John Farmer is national political correspondent for The Star-Ledger of Newark, N.J.