Last fall Paul O'Neill, then Secretary of the Treasury, wanted a simple answer to a thorny question: How prepared was the nation today to pay all its future bills? Two government experts worked for months to calculate the answer. Their findings, which shocked even them, were never published—the Bush administration made sure of that. The reason for the silence was that by the time the two researchers had completed their study, O'Neill had been thrown out of the Treasury and replaced by the more politically astute John Snow. No savvy administration power player would dare point out, right in the...