Washington, D.C.

David Walker sounds like a modern-day Paul Revere as he warns about the country's perilous future. "We suffer from a fiscal cancer," he tells a meeting of the National Taxpayers Union, the nation's oldest anti-tax lobby. "Our off balance sheet obligations associated with Social Security and Medicare put us in a $56 trillion financial hole—and that's before the recession was officially declared last year. America now owes more than Americans are worth—and the gap is growing!"

His...