"There should be a special circle in hell for people who mess with scientific data."

So sayeth Chris Mooney, who is - unlike most journalists - actually on top of these things. See his Prospect story here. But also see this Think Progress summary of the blatant Lysenkoism practiced by this White House. And for the most recent jaw-dropping example, the LA Times has a story on White House manipulations of a study on the harmful impacts of cattle grazing on government lands. It begins:

The Bush administration altered critical portions of a scientific analysis of the environmental impact of cattle grazing on public lands before announcing Thursday that it would relax regulations limiting grazing on those lands, according to scientists involved in the study.

A government biologist and a hydrologist, who both retired this year from the Bureau of Land Management, said their conclusions that the proposed new rules might adversely affect water quality and wildlife, including endangered species, were excised and replaced with language justifying less stringent regulations favored by cattle ranchers.
[---]
The original draft of the environmental analysis warned that the new rules would have a "significant adverse impact" on wildlife, but that phrase was removed. The bureau now concludes that the grazing regulations are "beneficial to animals."

Eliminated from the final draft was another conclusion that read: "The Proposed Action will have a slow, long-term adverse impact on wildlife and biological diversity in general."

Also removed was language saying how a number of the rule changes could adversely affect endangered species.

The whole story is worth reading, especially if your heart and respiration rates have been sluggish recently. (Reports like these are as close as I get to aerobics on days when I'm caged in my cubicle.)