The Secretary of State, in a Washington Post op-ed, sums it up nicely. Here's an excerpt:
Kay and his team have "discovered dozens of WMD-related program activities and significant amounts of equipment that Iraq concealed from the United Nations during the inspections that began in late 2002. The discovery . . . has come about both through the admissions of Iraqi scientists and officials concerning information they deliberately withheld and through physical evidence of equipment and activities that the Iraq Survey Group has discovered that should have been declared to the U.N."