Ten years ago next month, a bipartisan majority in Congress and a Democratic president launched America's welfare policy in a new and largely uncharted direction. It would be difficult to exaggerate the predictions of doom hurled against the Republican welfare reform bill signed by President Clinton on Aug. 22, 1996. Mr. Clinton had previously vetoed two versions of welfare reform when, with skill, daring and persistence, Republicans in the House and Senate pushed it through Congress a third time and put it again on the president's desk. In an act of remarkable political courage, Mr. Clinton defied senior members of...