Peter Gleick violated a principal rule of the global-warming debate: Climate scientists must be better than their opponents.

Gleick, the president of the Pacific Institute for Studies in Development, Environment and Security, admitted Monday night that he dishonestly obtained fundraising and strategy documents from the Heartland Institute, an obnoxious anti-climate science think tank. In the process, he’s done more to discredit himself and his work than he has to expose cynicism and collusion among global-warming deniers.

It’s very tempting for scientists and their allies to employ to tactics of their over-aggressive critics. Yet the global warming camp must make an affirmative case for ambitious action on carbon emissions. Critics need only poke holes in the scientists’ arguments, or, as is so often the case in global warming debates, merely insist they’ve done so. Manipulation and perfidy work much better for the deniers.

Whatever the misdeeds of those who attack climate research, however braindead the opposition to climate scientists appears to be, advocates degrade themselves when they allow their frustrations to get the better of their ethical responsibilities. They lend credence to the (wrong) impression that both sides of the debate are equally worthy of criticism, that global warming is another ideological war that both sides fight deceitfully. In that context, those who want to spend lots of money to green the economy lose, and those who want to do nothing win. As Rick Santorum tours the country accusing climate activists of treachery and conspiracy, this should be only more obvious.

Even if manipulative tactics and messaging were a more effective way to advance the fight against global warming, the inherent dishonesty of such a campaign should be odious to anyone who claims to prize substantive evidence over political positioning, particularly as one advocates imposing costs across human society.

Taking the high road is not easy or fun. But Gleick and the rest of us who favor decarbonizing the world economy have to be, and should want to be, the adults in the debate. Gleick’s confession and apology Monday are more than climate scientists ever got from deniers for the overblown “Climategate” e-mail scandal. But it would have been far better if he hadn’t needed to provide either.

UPDATE, Feb. 22, 1:45 p.m.:At Forbes, climate-change skeptic Warren Meyer calls for a more rational climate debate. And, on his blog, Meyer criticizes me (with some reason) for lumping all climate skeptics into the Santorum-conspiricist camp. He’s right that not every last climate skeptic is a Rick Santorum or a Rick Perry. But, unfortunately, their side of the debate is so often dominated by people worthy of the language I used — people who, for example, cling to out-of-context quotes from Climategate as proof of some international plot to steal Americans’ liberties, or state officials such as Virginia Attorney General Kenneth Cuccinelli (R), who uses the powers of his office to hound climate researchers at local universities. I wish that weren’t so, and it was in fear of climate scientists themselves descending into political ma­nipu­la­tion that I wrote. So I’d like to amplify Meyer’s call for making the discussion about the science, not ideological attacks.