As U.S. forces closed in on Baghdad on Friday, a civilian official at the Pentagon rejoiced at the success of American arms but worried about things that had not happened. Weapons of mass destruction neither have been used by Saddam Hussein's legions nor found by the invading Anglo-American coalition.

The absence so far of WMD does not diminish justification, in the view of U.S. policymakers, for changing Baghdad's dictatorial regime. Nevertheless, they would like to collect real evidence of weapons. ''If we don't,'' said the official, ''you can bet the liberals will make a big deal out of it.''

White House and State Department officials were saying the same thing two weeks earlier. On March 24, a mid-level Bush administration official told me he feared that modest quantities of chemical weapons would constitute the entire cache of captured weapons of mass destruction, but added that he would be grateful for that much. The official, an early advocate of Iraqi regime change, is not fretting about the decision to go to war but about the global reaction to it.