When we talk about hypocrisy in politics, we usually highlight personal behavior. The multiply-married politician who proclaims "family values" while also having affairs is now a rather dreary stock figure in our campaign narratives.

But the hypocrisy that matters far more is the gap between ideology and practice that has reached a crisis point in American conservatism. This Republican presidential campaign is demonstrating conclusively that there is an unbridgeable divide between the philosophical commitments conservative candidates make before they are elected and what they will have to do when faced with the day-to-day demands of practical governance. Conservatives in power have never been -- and can never be -- as anti-government as they are in a campaign. 

Begin by asking yourself why so many conservative politicians say they're anti-government but spend long careers in office drawing paychecks from the taxpayers. Also: Why do they bash government largesse while seeking as much of it as they can get for their constituents and friendly interest groups?  

Why do they criticize "entitlements" and "big government" while promising today's senior citizens -- an important part of the conservative base -- never, ever to cut their Medicare or Social Security? Why do they claim that they want government out of the marketplace while not only rejecting cuts in defense but also lauding large defense contracts that are an enormous intrusion in the operation of the "free market"? 

The contest between Mitt Romney and Rick Santorum is unearthing all sorts of double standards of this sort, and I salute each of them for drawing attention to the other's inconstancies. 

Santorum scored a direct hit on Romney last Thursday in a speech at the Detroit Economic Club. Both Romney and Santorum opposed President Obama's rescue of the auto industry, a form of direct government intervention whose success Republicans (though not, it appears, Michigan's voters) have a hard time acknowledging.

But Santorum raised a good question. "Governor Romney supported the bailout of Wall Street and decided not to support the bailout of Detroit," Santorum said. "My feeling was that...the government should not be involved in bailouts, period. I think that's a much more consistent position."

Indeed it is. Romney can offer all sorts of rationales for the difference between the two bailouts, but once he backed the Wall Street rescue, he could no longer claim free-market purity. The financial bailout he thought was so vital created the very "dependency" and sense of "entitlement" within our privileged classes that he condemns when it comes to the less well-off.

Many conservatives -- including, bravely, George W. Bush -- pushed for the bank bailout because the alternative was a catastrophic collapse of the financial system. But having done so, could they please stop claiming they are free market virgins? They gave that up long ago.

Santorum has a long list of ideological heresies of his own to defend. They include his eagerness to win federal earmarks, a habit he shares with Romney, as the Washington Post's Rosalind Helderman recently reported. 

There is also the critique that Romney's super PAC is making in an ad airing in advance of Michigan's February 28 primary: It attacks Santorum for regularly voting to increase the debt ceiling when he was a senator from Pennsylvania.

This is the same Santorum who supported congressional conservatives last year when they blocked a debt-ceiling increase in pursuit of more budget cuts. "We cannot continue to write blank checks that our nation cannot cash," Santorum said -- the very blank checks he freely endorsed when he was in the Senate. True, both parties have played games on the debt ceiling, but never to the point of undermining the federal government's credit standing, as the Republicans did last year.

Of course Santorum was only doing the responsible thing when he was a senator, but he cannot really defend what he did in the past without acknowledging that what he said more recently is flatly contradicted by his own behavior.

Can conservatives finally face the fact that they actually want quite a lot from government, and that they are simply unwilling to raise taxes to pay for it?

This is why our political system is so broken. Conservatives keep pretending that they can keep anti-government promises that they know perfectly well they are destined to break. We won't have sensible politics again until our friends on the right bring their rhetorical claims into closer alignment with what they do -- and what it takes to make government work.

(c) 2012, Washington Post Writers Group