THAT A RECENTLY rediscovered 2009 op-ed column on health care by Mitt Romney can be seen as embarrassing evidence of disqualifying moderation is a sad signpost of how far the Republican Party has drifted toward the irresponsible right, and how quickly.

The USA Today op-ed, a critique of President Obama’s health-care reform plan then being debated in Congress, is in fact conservative, rational and responsible — what you’d hope for from a constructive opposition. To see Mr. Romney placed on the defensive by such advocacy is of an alarming piece with Newt Gingrich fleeing from his recent positions on climate change and Rick Santorum recanting his support for conservative education reform.

The essay was brought back to public attention this month by the Web site BuzzFeed, which at first reported that the op-ed was not to be found on USA Today’s site. That gave birth to dark, conspiratorial thoughts in Rick Santorum’s mind, as he confided to conservative radio host Laura Ingraham. “You know, it’s really interesting, Laura, that the USA Today op-ed was somehow removed from the archives,” Mr. Santorum said. “Now, I don’t know how that happens.”

Sadly for this line of reasoning, BuzzFeed later acknowledged that the Romney op-ed was, in fact, still archived on the newspaper site. But never mind: The more damning truth remained. In the essay, Mr. Romney accepts as a legitimate public goal that all Americans should have health insurance. He expressed pride that Massachusetts under his leadership had come close to insuring everyone in the commonwealth. He didn’t use the dread word “mandate,” but he pointed out, pragmatically, that people could be encouraged toward buying insurance with tax credits or discouraged with tax penalties from becoming “free riders.”

Not long ago, this was accepted as sensible both morally (no one should die for lack of insurance) and pragmatically (if too many young, healthy people spurn insurance, the costs for everyone else will soar). Now it’s Republican heresy.

Perhaps more damning, Mr. Romney’s op-ed was focused on constructive criticism: He urged a bipartisan solution. He cited cost control as the biggest challenge and offered some practical approaches. In the Republican presidential dialogue, insuring the uninsured and controlling costs, upon which the nation’s future depends, are rarely debated. The loudest contest — with Mr. Romney an enthusiastic participant — is who can promise to repeal Obamacare first.

The Republican side of the climate change debate, not very long ago, favored market-based solutions such as cap-and-trade as a conservative alternative to carbon taxes. Now solutions don’t figure in the discussion; the problem can’t even be acknowledged. Mr. Santorum spent the better part of the past decade championing President Bush’s education reform, because it called for more accountability and parental influence. Now he says that it was all a big mistake — he was acting “against the principles I believed in,” he says — because virtually no federal role is permissible. And, no matter how low revenue falls, taxes can always be lowered but never be increased.

This constricting orthodoxy doesn’t seem conducive to electoral success. Maybe that’s not our problem. But it doesn’t seem conducive to national progress, either. That’s everyone’s problem.