From the AP:
"The Smithsonian Institution toned down an exhibition on Arctic climate change, fearing that it would anger Congress and the Bush administration, a former museum administrator said. The official text of the exhibition was rewritten to minimize and add uncertainty about the relationship between global warming and people, said the former official, Robert Sullivan, who was associate director in charge of exhibitions at the National Museum of Natural History. Officials omitted scientists’ interpretations of some research and let visitors draw their own conclusions from the data, Mr. Sullivan said. In addition, graphs were altered 'to show that global warming could go either way,' he said. Museum officials denied that political concerns had influenced the exhibition, saying the changes were made to increase objectivity."
More complete version here. Sullivan is quoted as saying of Smithsonian administrators "The obsession with getting the next allocation and appropriation was so intense that anything that might upset the Congress or the White House was being looked at very carefully."
This reminds me of the Smithsonian's Enola Gay controversy back in the mid-90s, which is captured well here.