It’s a lovely thing when the conventional wisdom proves to be so spectacularly wrong. The entire Democratic Party, not to mention the media establishment, simply took as a given that suave, charming, effulgent, numinous President Barack Obama would mop the floor with grumpy, truculent, sardonic former Vice President Dick Cheney. And yet, on almost every issue he has championed since he left office, Cheney has won the debate or at least put the White House on the defensive. From the closing of Gitmo and the placement of terrorists in domestic prisons, to the release of the torture memos and the aborted release of prisoner-abuse photos, Cheney holds the higher ground politically, or in the polls, or both.

Many liberals who take it on faith that Cheney represents all that is evil, cruel and unhip about the Republican Party, not to mention carbon-based life forms, are loath to give him even an ounce of credit for his success. That Obama is backpedaling or off-balance on so many fronts, they say, is at best circumstantial evidence that Cheney is having any effect. Well, you know, Thoreau was right: “Some circumstantial evidence is very strong, as when you find a trout in the milk.” The trout in Obama’s milk is the trout fisherman from Casper, Wyo.

There are profound lessons to be learned here. An easy one is that the Bush policies Democrats relentlessly demonized were hardly as extreme, politically or morally, as they alleged. If Bush’s anti-terror policies were half as bad as Obama & Co. claimed, the American people and Congress would reject them all wholesale, and Cheney’s arguments would sound like the ravings of a madman. That hasn’t happened.

But the more important lesson, at least for conservatives and Republicans, is that arguments matter. If personalities and politics alone drove the issues, then of course flannel Cheney would lose against silky Obama. But it turns out that substance is a good counterpunch to style.

That’s worth remembering as the GOP figures out how to deal with Obama’s nomination of Sonia Sotomayor to the Supreme Court. Conservatives think she’s wrong on the merits, and even though they will almost surely fail to block her confirmation, there’s no reason for them to be ashamed of their stance. If liberals want to call conservatives racist or sexist for opposing the first Hispanic female nominee to the court, conservatives should patiently explain that they wouldn’t want to insult her with the soft bigotry of low expectations. After all, if Sotomayor were a rich white male with exactly the same views and philosophies, you can be sure conservatives would oppose her just as vigorously.

But the lesson runs deeper than the impending Sotomayor battle. Conventional wisdom also tells us that the GOP needs to become more inclusive. On this score the conventional wisdom is right, if by “inclusive” you mean getting more people to join the party and vote Republican. But many people mean something else by “inclusive.” They think the GOP needs to become the Pepsi to the Democrats’ Coca-Cola, indistinguishable save for small matters of taste and marketing.

The conventional wisdom holds that conservatism is in trouble because the GOP is in trouble. But the two are not one and the same. Indeed, the GOP’s conservative principles aren’t necessarily the main reason for its unpopularity. Arguably, Republicans’ failure to adhere to their principles when in power hurt them more. The most recent Pew Research Center report on “Trends in Political Values and Core Attitudes” finds that 37 percent of Americans describe themselves as conservative, while only 19 percent describe themselves as liberal. And conservative principles are still competitive, even after eight years of Bush, a staggering recession and the most popular Democratic president in nearly a half-century. A majority of respondents say the “federal government controls too much of our daily lives” and that “government regulation of business usually does more harm than good.”

Obviously, the GOP is not in an enviable position. But conservatives have been in worse shape countless times before. What they have done each and every time is argue their way forward. Goldwater, Reagan and Gingrich each mounted conservative victories by making arguments for their cause.

The cliché is that politics is about “addition,” and the GOP needs to add more Hispanics, or gays, or women to its coalition, as if such descriptors define people more than their individual aspirations. Republicans will never win that fight, nor should they try to out bean-count the Democrats. Persuasion should trump the pandering of “addition.” Conservatives must argue why they are right, not endlessly apologize for their alleged wrongs.

And the surest way to lose that argument is by failing to even try to make it. If anything, conservatives owe Dick Cheney gratitude for demonstrating that.

© 2009 Tribune Media Services, Inc.