The response in the US to startling new allegations that the White House directed the forgery of evidence to support its case for the war in Iraq has been surprisingly muted so far. The charges may be false, of course, but if they are seriously examined and turn out to be true, this is - or ought to be - a Watergate-sized scandal.

Ron Suskind is a heavyweight: a Pulitzer Prize-winning journalist, and the author of a well-regarded book on the administration's security policies, The One Per Cent Doctrine. His new book, The Way of the World: A Story of Truth and Hope in an Age of Extremism, which was published last week, contains the extraordinary new charge. It says that late in 2003 the White House ordered the Central Intelligence Agency to forge a memo dated July 2001 from Tahir Jalil Habbush, Saddam Hussein's intelligence chief, to Saddam himself, affirming that Mohammed Atta, the September 11 2001 bomber, had contacts with the regime and that Iraq had an ongoing weapons of mass destruction programme.

This document has long been known about. It was splashed in the British press in December 2003, when The Sunday Telegraph reported on it. That story briefly entertained the possibility that the memo was phoney but insisted it was well vouched for by Iraqi sources. Reports in the US subsequently cast further doubt on it and the memo came to be seen as a fake. But up to now there has been no supported allegation from a reputable author that the White House and the CIA were behind it. That is what Mr Suskind alleges.

You can read the rest of my Monday column for the Financial Times here.