The climate-change talks in Copenhagen provided another frank lesson to the rest of the world on the limits to a U.S. president's power.

Of course, it wasn't the first time they had been read to from that book. The Clinton administration 12 years ago boldly spoke about cutting emissions only to see the Senate vote down U.S. participation in the Kyoto accords.

So, with jaundiced eyes, delegates from the 191 other nations attending last week's global-warming confab opened their ears Friday to hear what President Obama had to say. But they probably only half-listened, knowing he had a tougher audience to face.

Congressmen opposed to Obama's cap-and-trade plan to address climate change have been spouting the "Climategate" tale about the English weather scientists' stolen e-mails. Rep. Jim Sensenbrenner (R., Wis.) said the e-mails "show a pattern of suppression, manipulation and secrecy." He called it "scientific fascism." It was hardly that.

If the deniers of global warming are so concerned about the science, they should heed the Union of Concerned Scientists. It said that what the hacked e-mails "show are simply scientists at work, grappling with key issues, and displaying the full range of emotions and motivations characteristic of any urgent endeavor."

An independent review of the e-mails by scientists working with the Associated Press also found "no evidence of falsification or fabrication of data." In other words, global warming is real and its dominant cause is human activity. So, what to do about it?

It became clear early on that no definitive answer would be arrived at in Copenhagen. Less developed nations wanted hard cash to compensate for reduced industrialization. China balked at the suggestion that its promised steps be monitored. A scramble for the weak pact reached on the conference's last day was disappointing.