The Presidential Candidates are Scared of Challenging Their Parties. They Shouldn't Be.

One of the few things the Republican and Democratic presidential contests have in common is the relentlessness with which candidates on both sides are wrapping themselves in orthodoxy. Heretics need not apply.

It's true that primary contests are largely decided by the party faithful. And I'll concede that orthodoxy may be underrated since we tend to trust people whose views are grounded in a set of principles.

"I did try to found a heresy of my own," said G.K. Chesterton, who wrote the book on orthodoxy, "and when I put the last touches to it, I discovered that it was orthodoxy."

But if ever there were an election that demanded a break with the past, it is surely 2008. Whoever takes over from President Bush will face genuinely unprecedented problems. Yet here are the Republicans bickering over who is the "true conservative" while Democrats scrupulously police their ranks for any signs of deviationism.

Mitt Romney--stealing and reworking a line that Howard Dean swiped from the late Sen. Paul Wellstone--declares himself a member of "the Republican wing of the Republican Party."

Nonsense, says John McCain who observed of the former governor: "As we all know, when he ran for office in Massachusetts, being a Republican wasn't much of a priority." True, but being a good Republican hasn't always been McCain's highest priority, either. The pressure to play the orthodoxy card is immense this year.

That's why Romney and former New York City Mayor Rudy Giuliani spar over who was the biggest tax cutter when each ran a liberal, high-tax jurisdiction. From the Republican point of view, that's a bit like arguing about who ran the most pious gin joint.

Then there's Fred Thompson, who thinks that all he has to do is reincarnate Ronald Reagan. He says the economy is just "rosy" and, like his opponents, believes low taxes heal all.

It's true that there are some modest signs of rethinking, and even apostasy. McCain saw a need to put out a health plan, even if it places more faith in market solutions than experience would justify, and he suggests ways to help workers displaced by free trade. Thompson talks about cutting Social Security benefits--though the cuts he proposes would be too severe and his view is well within the orthodox conservative worldview.

At least two Republicans, Rep. Ron Paul and former Arkansas Gov. Mike Huckabee, are preaching that the old faith is in need of reformation. Paul represents a refreshing if doctrinaire brand of libertarianism. Huckabee speaks with passion about the costs of inequality and sometimes sounds as if he's shown up for the wrong party's debate. You wonder: Will Huckabee, who is slowly rising in the polls, force the front-runners to notice that even the faithful have quiet doubts about whether Ronald Reagan's answers--however appropriate they might have been to 1980--respond to the questions of today?

Among Democrats, the great mystery is why Barack Obama is not running stronger. The answer may be that Obama is waging two campaigns at the same time. He runs to Hillary Clinton's left--most recently by criticizing her vote to declare Iran's Revolutionary Guards a terrorist group. Yet he also casts himself as a young, untainted leader who will help the country break out of the stale debates and miserable divisiveness of the 1960s, the 1990s and the Bush Era.

To have a chance at winning, Obama may have to choose. Since there is plenty of room for the unorthodox option, he might do better rediscovering the original break-with-the-past promise of his candidacy.

As for the soaring Clinton, she seems torn between running a primary campaign to reassure the left and a general election campaign. She tries to make up for her vote authorizing the war in Iraq with fervent anti-war rhetoric and she diminishes the significance of the Iran vote. At the same time she will be able to cite those votes as evidence of her toughness.

Despite a slew of relevant policy proposals, her biggest long-term burdens are the perception that she's too calculating and that her victory might be more about restoration than renovation. The latter is what most voters want, meaning that she, no less than Obama, has an interest in proving that her party's purpose is not just to replace one orthodoxy with another. As for the GOP, the candidate who finds the courage to challenge the party's ruling ideas may be the only one who can save it.

E. J. Dionne, Jr. is a columnist for The Washington Post, a senior fellow at the Brookings Institution, and a professor at Georgetown University.

By E. J. Dionne, Jr.