Fresh evidence emerged last week that the White House can't tell the difference between fashioning policy and spinning the facts to suit its own politics. Most administrations share this problem to a degree, but it's far worse when the White House decides to tighten its grip on federal regulators at the expense of those who write the laws.

   First, to the case in point. Government scientists claim the Bush administration has been trying for two years to force them to soften their findings on global warming. Complaints about interference were aired at a House hearing last week where a survey of nearly 300 scientists in seven agencies studying the subject found that almost half had experienced or heard about pressure to downplay warnings about the growing amount of evidence of climate change and global warming.

   The scientists said Phil Cooney, a former oil-industry lobbyist who at the time headed the White House's Council on Environmental Quality, had blue-penciled reports about the effects of climate change on human health and the environment. Rep. Henry Waxman, D-Calif., said Cooney, who now works for ExxonMobil, had "imposed his own views on the reports scientists had submitted to the White House."

   Waxman called it an "orchestrated campaign to mislead the public about climate change."

   Call it the fox guarding the henhouse. This is not the first time the administration has been accused of politicizing science, but it comes at a time when the White House has decided to assume more control over the regulatory process. An executive order signed by President Bush orders each federal agency to have a regulatory-policy office run by a political appointee.

   Regulations are a way to spell out how to conform to legislation passed by Congress. It doesn't take a political scientist to understand that putting the process under the direct control of White House appointees enhances the president's authority over domestic government and diminishes the role of Congress. The timing, just after the Democrats claimed Capitol Hill, surely is no coincidence.

   The move fits neatly within the administration's pattern of boosting presidential power at every turn, without regard to the system of checks and balances. The president's habit of issuing "signing statements" that outline which provisions of new laws he will enforce and which he will ignore is another example of this imperial intention.

   Congress can fight this dangerous tendency by giving closer scrutiny to White House appointees. They should reject those who are clearly unfit or have a conflict of interest, such as former oil lobbyists making decisions about the quality of the air we breathe.