N ASA’s detractors take delight in coming up with derisive ways to spell out the acronym by which the U.S. space agency is familiarly known. Not a Serious Agency is one such jab; Never a Straight Answer is another.

Now, thanks to the antics of some in NASA’s Office of Public Affairs, the agency appears to be living up to those characterizations.

According to James E. Hansen, director of NASA’s Goddard Institute for Space Studies, political appointees in the NASA press office have tried to prevent him from sharing his views on global warming, which, not coincidentally, don’t mesh with those of the White House. Dean Acosta, NASA’s top spokesman, initially denied that there was anything wrong or out of the ordinary going on but later admitted that actions taken by a young political appointee were out of line.

NASA must act decisively to correct the problems brought to light by this episode, lest its credibility as a scientific institution suffer permanent damage.

Scientific openness is a vital principle that must be reinforced, and NASA Administrator Michael D. Griffin’s call for a clarification and update of agency policies governing the release of scientific data is a step in the right direction. So was the resignation — albeit for apparently unrelated reasons — of George Deutsch, the political appointee in NASA’s press office implicated in what appears to be a thoroughly clownish yet disturbing attempt to muzzle Dr. Hansen.

Some at NASA have suggested that Mr. Deutsch’s departure solves the problem, but that is not believable. Since when does a 24-year-old former campaign intern, acting alone, have the clout to direct how NASA’s Office of Public Affairs handles one of the agency’s preeminent scientists?

It appears certain that Mr. Deutsch had the support or encouragement of more-senior officials, either at NASA headquarters or even at the White House.

It is clear that at minimum, Dr. Hansen was singled out for special scrutiny by NASA’s Office of Public Affairs. The evidence includes e-mail exchanges in which Mark Hess, the 30-year veteran who heads public affairs at NASA’s Goddard Space Flight Center, which oversees the Goddard Institute, questioned whether monitoring Dr. Hansen’s comings and goings was an appropriate role for his office. The e-mail made clear that this direction came from NASA headquarters, and that among the items Mr. Hess was told to keep tabs on were all scientific papers coming out of the Goddard Institute.

Mr. Acosta can make the claim that it is standard procedure to have scientists and engineers coordinate press releases and public appearances with the press office, but this goes well beyond coordination.

Mr. Hess’s e-mail also makes note of the fact that NASA Associate Administrator for Space Science Mary Cleave, and her deputy, Colleen Hartman, were assigned the right of first refusal to all interview requests placed with the Goddard Institute. Although that practice could be justified in the name of obtuse bureaucratic protocol, it is not standard procedure and in this case is highly suspicious.

It is suspicious for a number of reasons, including the fact that a number of scientists have accused the administration of George W. Bush of routinely ignoring or even suppressing research findings and advice that do not fit with its political orthodoxy. Warnings of the dangers posed by global warming certainly fall within that category.

Some might reasonably question whether Dr. Hansen’s views are not alarmist, but scientists are in wide agreement that the phenomenon of global warming is real. NASA has been assigned the critical task of evaluating global warming, presumably to aid in developing a scientific and political consensus on how to deal with it. To ignore or suppress the agency’s contribution to what could be the most important environmental debate of our time is not only extremely wasteful, it is flat-out irresponsible.

It makes a complete mockery of NASA, calling into question just about everything the agency does — not just its Earth science activities. NASA already is on thin ice with some in the scientific community, a group whose support is critical to the fragile political consensus now behind the agency’s plan to return astronauts to the Moon next decade.

It is now up to Dr. Griffin — as if he did not have enough on his hands — to thoroughly investigate this embarrassing episode. Anyone found to have been part of any effort to intimidate or browbeat scientists into publicly towing a certain political line should at minimum be removed from the Office of Public Affairs. Better yet, they should be banished from the agency to which they have done such a great disservice.

The House Science Committee, meanwhile, should not back away from its own investigation into this matter until it is completely satisfied that this unacceptable situation has been resolved.