Thousands of Republican politicians, activists and partisans are now lining up behind John McCain and preparing to advance into the fall campaign. If they hope to win, many pundits maintain, their task is obvious: Ditch conservatism, which is intellectually bankrupt.

That might make sense if you equate the Republican Party with conservatism. The governing style that culminated in the GOP's defeat in 2006, however, shows that Republicans have suffered largely because they haven't been conservative enough. In his unsuccessful bid to become minority leader in the House, Rep. Mike Pence stated the problem plainly.

"We are in the wilderness because we walked away from the limited government principles that minted the Republican Congress," he warned his colleagues. "The American people did not quit on the Contract with America, we did."

He's right. While in control of Congress, Republicans could have led the nation toward market-based reforms in Medicare, a program that threatens to overwhelm the federal budget in coming years. Instead, they made the problem worse: They passed a Medicare drug benefit that will leave our grandchildren saddled with trillions of dollars in liabilities.

Republicans could have advanced their professed commitment to limited government and fiscal responsibility. Instead, they more than doubled the size of the federal government, hiding their pork in the plain brown wrappers of anonymous earmarks. 

Imagining that they could continue to govern by pretending to be conservatives, Republicans have repeatedly betrayed - and finally lost - the trust of their most loyal supporters. The way to win in 2008 is to earn that trust back, since the American people remain committed to conservative ideas.

Look no further than McCain and his Democratic opponent, Barack Obama. On the campaign trail just a few months ago, Obama was offering the usual soak-the-rich rhetoric on taxes. Indeed, his campaign floated the possibility of raising capital gains and dividends on the wealthy up to an economy-chilling 28 percent. But when his plan was finally published this month, the rate was only 20 percent. His overall tax plan is still riddled with problems, of course. But his concession on cap gains suggests that conservatism's insistence on lower taxes remains appealing.

For his part, Republican McCain now embraces the conservative position on immigration. Once a leader in the attempt to provide amnesty to millions of illegal residents, he now presses for a border fence. And both candidates have moved to the right on energy, with each now stumping for more drilling in domestic waters.

But what about Social Security and Medicare? To New York Times columnist Paul Krugman, the popularity of these programs proves that America never was a conservative nation. But such a statement presupposes that conservatives want to get rid of the social safety net. If that were true (and some conspiracy mongers, of course, will always believe that it is), then why have conservatives been the loudest in warning that these programs are headed for financial collapse? And why would they be offering free-market ways to salvage them?

Beginning in the 1950s, conservatives forged a political philosophy and, over the next several decades, built an intellectual infrastructure to popularize their principles and apply them to policy problems. And they found political leaders who could implement those solutions.

In short, conservatism advanced because conservatives refused to get in tune with the times. They possessed the moral vision and intellectual courage to compose a better tune. They offered leadership, and they accepted the responsibilities that go with it.

But too many Republicans have spent the last several years demonstrating that they can't be trusted to lead. McCain seems to understand this, at least when it comes to spending.

"The size of government in the last five years has grown more rapidly than any time since the Great Society," the Republican nominee-to-be pointed out in a 2005 speech at The Heritage Foundation."That's not the path we should have trod in response to the American people giving us control of both houses of Congress in 1994." If they want to regain power, Republicans would be wise to re-embrace conservative principles.

Liberalism is a bankrupt philosophy that has been tried and found wanting in one major policy issue after another, from national defense to social welfare, from education to the national economic policy. That's why candidates run away from liberal ideas when it's time for a general election.

Republicans must run toward conservative policies if they want the tides of history to sweep them back into power.

Ed Feulner is president of The Heritage Foundation (heritage.org).