These days, the question I hear most from political comrades is: “What the hell happened to you?”

Okay, okay, my old friend Andrew Coyne put it a little more politely than that in a recent magazine column. Here’s what he actually wrote: “Things have come to a pretty pass in the Republican Party when David Frum is the mushy moderate of the piece.”

I feel exactly the same way! So if it’s not too personal, let me request a few minutes of your time to explain how I ended up being bashed by Rush Limbaugh on the airwaves — and taking a few shots of my own in the pages of Newsweek.

Like so many in my age cohort, I became a conservative in the crisis years of the late 1970s. Inflation was raging, economic growth had stalled, social order seemed to be breaking down, and the democratic West seemed to have lost its nerve and confidence in the struggle against its enemies.

Conservatives had answers to these problems: cut taxes, reduce government, repeal price controls, print less money, jail criminals, trust individuals, rebuild armed forces, strike back against terrorists and hostage-takers.

These ideas were tested, and they worked. Many conservatives were frustrated that we did not succeed more completely. I know: I was one. My first book, published in 1994, lamented that Reaganism had reached its political limits. I predicted that Republicans would continue to win elections, but warned that these election victories were ceasing to produce political results.

Both those predictions proved accurate. Republicans won smashing political victories in 1993 and 1994: capturing the mayoralties of New York and Los Angeles in 1993, winning control of both houses of Congress in 1994. They implemented new anti-crime policies and enacted welfare reform. The number of murders dropped by more than one-third nationwide, by more than two-thirds in New York City — launching an American urban renaissance.

I moved to Washington, D.C., in 1996. And there I began to notice something disturbing. While the congressional victory of 1994 had ceased to produce much in the way of important conservative legislation, it sure was producing a lot of wealth for individual conservatives. They were moving from the staff offices of Congress to lobbying firms and professional associations. Washington (to quote something I’d write later) began to feel like a giant Tupperware party, where people you had thought of as friends suddenly seemed always to be trying to sell you something. Acquaintances of mine began accepting all-expense-paid trips to the South Pacific from Jack Abramoff.

Whenever things get tough for the Republican party, conservatives will draw a separation between (good, pure) philosophical conservatism and (compromised, tainted) Republican politics. But the people who began making a lot of money out of politics in the 1990s did so precisely as conservatives. “Here’s why conservatives should support Microsoft, not Netscape,” they would explain. “AT&T is right from a conservative point of view, and Verizon is wrong,” another would chime. “Conservatives cherish federalism — and that’s why we must insist that electrical utilities continue to be regulated by the state power commissions!”

George Bush narrowly won the presidency in 2000, and I was recruited to join the administration as a speech-writer. My initial brief was domestic policy and economics, and it soon become impossible to avoid noticing that the administration’s economic policies were not working very well.

Even as it fought wars in Iraq and Afghanistan, the administration dramatically increased domestic spending (including the first permanent new entitlement program since 1974, the hugely costly prescription drug benefit for senior citizens). Taxes were cut in 2001 and 2003. Big deficits ballooned and a great consumption boom exploded. The stock market and the housing market soared — but median wages stagnated.

There were many reasons for this stagnation. Some 10-million people migrated to the United States between 2000 and 2006, at least half of them illegally, exerting terrible downward pressure on wages for the less skilled. Health care costs surged over the Bush years. A policy to cover a family of four doubled in price in just six years, to over $13,000. After employers paid that high price, they had little if anything left over for wage increases.

Conservative economic policies, which had saved the United States and the other advanced democracies from stagnation in the 1980s, suddenly seemed bereft of answers for the economic challenges of the 21st century.

This worried me. What worried me even more was how little it seemed to worry so many of my friends and colleagues from the conservative world and the Bush administration. A quarter century before, Ronald Reagan’s budget director David Stockman had famously said that it was the job of conservatives to attack weak claims, not weak claimants. We would creatively use the power of freedom to improve conditions for everyone. What had happened to that idealistic drive?

So much of our energy was being absorbed instead by cultural battles left behind from the unfinished business of the 1960s and 1970s. Here, too often, we were on the wrong side of history: Back in the 1960s and 1970s, we’d been fighting to protect the common-sense instincts of ordinary people from elite interference. Now, in the Terri Schiavo euthanasia case, with stem cell research, on gay rights issues, it was we who had become the interfering elite, against a society that was reaching its own new equilibrium.

Of course, that’s not how conservatives saw it. We saw a country divided in two, red states and blue, NASCAR vs. NPR, real America against the phonies in the cities. A movement that had begun as an intellectual one now scornfully pooh-poohed the need for people in government to know anything much at all. But expertise does matter, and the neglect of expertise leads to mismanagement and failure — as we saw in Iraq, in Katrina and in the disregard of warning signals from the financial market. It was under a supposedly pro-market administration that the United States suffered the worst market failure of the post-war era, and that should have sobered us. Instead, we rallied to Sarah Palin and Joe the Plumber.

Disregarding evidence and expertise, we shrugged off warnings of environmental problems. One consequence: In 1988, the elder George Bush beat Michael Dukakis among voters with four-year degrees by 25 points. In 2008, Barack Obama won the BA and BSc vote, the first Democrat to do so since Lyndon Johnson in 1964.

Conservatives stopped taking governance seriously — and so Americans ceased to trust conservatives in government.

So that’s the answer to the question in the first paragraph. I don’t think I’ve changed my mind about fundamental principles. I still champion liberty and individuality, still advocate markets and entrepreneurship, still insist on free trade and open markets. My social preferences remain conservative, and I believe fervently in strong American international leadership.

But on environmental issues, we have to follow the evidence where it leads — and on social issues we have to take our society as it is. If the world changes, we have to change with it. The refusal of so many of my fellow conservatives in the United States to adapt their thinking to facts and realities does not demonstrate their adherence to principle. It demonstrates a frivolous indifference to the responsibilities of political leadership.

The argument in which I’ve been engaged, and which prompted Andrew’s funny quip, is an argument (as I see it) over what conservatism should be: Is it a philosophy of government? Or is it an expression of cultural alienation? Is it politics or is it protest?

With horrible irony, I see my fellow conservatives in the United States opting out of politics at exactly the moment when they are most needed. The Obama administration is careening toward a more expensive and interventionist government, toward reckless spending and destructive taxation. This is where I came into politics 30 years ago, and I will stand again on the same side I stood then. But now as then, my side will only be successful to the extent it is knowledgeable, to the extent it is public-spirited, to the extent that it is based on evidence and research, to the extent that it advocates the greater good rather than the narrow interests and values of one class or one geographic section.

I don’t think of myself as having gone squishy. I think of myself as having grown sober. And my conservative critics? On them, I think the most apt verdict was delivered by Niccolo Machiavelli, 500 years ago: “This is the tragedy of man. Circumstances change, and he does not.”