WASHINGTON — A former senior C.I.A. official says that officials in the Bush White House sought damaging personal information on a prominent American critic of the Iraq war in order to discredit him.

Glenn L. Carle, a former Central Intelligence Agency officer who was a top counterterrorism official during the administration of President George W. Bush, said the White House at least twice asked intelligence officials to gather sensitive information on Juan Cole, a University of Michigan professor who writes an influential blog that criticized the war.

In an interview, Mr. Carle said his supervisor at the National Intelligence Council told him in 2005 that White House officials wanted “to get” Professor Cole, and made clear that he wanted Mr. Carle to collect information about him, an effort Mr. Carle rebuffed. Months later, Mr. Carle said, he confronted a C.I.A. official after learning of another attempt to collect information about Professor Cole. Mr. Carle said he contended at the time that such actions would have been unlawful.

It is not clear whether the White House received any damaging material about Professor Cole or whether the C.I.A. or other intelligence agencies ever provided any information or spied on him. Mr. Carle said that a memorandum written by his supervisor included derogatory details about Professor Cole, but that it may have been deleted before reaching the White House. Mr. Carle also said he did not know the origins of that information or who at the White House had requested it.