The Bush administration long ago secured a special place in history for the audacity with which it manipulates science to suit its political ends. But it set a new standard of cynicism when it allowed NASA's leading authority on global warming to be mugged by a 24-year-old presidential appointee who, quite apart from having no training on that issue, had inflated his résumé.

In early December, James Hansen, the space agency's top climate specialist, called for accelerated efforts to reduce industrial emissions of carbon dioxide and other gases linked to global warming. After his speech, he told Andrew C. Revkin of The Times, he was threatened with "dire consequences" if he continued to call for aggressive action.

This was not the first time Dr. Hansen had been rebuked by the Bush team, which has spent the better part of five years avoiding the issue of global warming. It was merely one piece of a larger pattern of deception and denial.

The administration has sought to influence the policy debate by muzzling the people who disagree with it or -- as was the case with two major reports from the Environmental Protection Agency in 2002 and 2003 -- editing out inconvenient truths or censoring them entirely.