WASHINGTON -- The ever nastier Washington fight between former counterterrorism chief Richard Clarke and manifold Bush officials has taken on a "he said/she said" quality. It's hard to know who to believe. But having routinely undercut his credibility elsewhere, President George W. Bush should bear the burden of proof vis-a-vis Clarke.

While Clarke was making his case before the 9/11 commission, Medicare's chief actuary, Richard Foster, was telling the U.S. Congress that he shared estimates of the burgeoning cost of the proposed Medicare drug bill with administration officials last summer. Yet former Medicare administrator Thomas Scully threatened to fire Foster if the latter released the estimates to legislators.

"We can't let that get out," Foster says Scully told him. Health and Human Services Secretary Tommy Thompson has reluctantly ordered an investigation, but that's not nearly enough.