World War I influenced unemployment reform in contradictory ways. The downturn of the American economy caused by the outbreak of the war in Europe stimulated an intensified quest for alleviative means, as described in the previous chapter. The entry of the United States into the war in April 1917, on the other hand, interrupted what might be called the natural development of reform. Unemployment ceased to be a generally noticeable problem, and further exploration into the potential of remedies such as the use of public works or unemployment insurance essentially came to a standstill. But the partial abandonment of the time-honored principles of laissez-faire that characterized much of the war effort brought unexpected prominence and growth to the favorite remedial instrument of the prewar period, the labor exchange. The USES, spurred on by the need to overcome the labor shortages caused by wartime production, developed into an imposing, nationwide organization. The growth of the USES constituted in many ways the fulfillment of the most ardent dream of the reformers, because it offered the chance to effect the intercity and interstate exchange of workers that many considered to be a necessary step in fighting unemployment. Unfortunately for the reformers' expectations, the haste of the wartime buildup produced shortcomings in the structure and performance of the service that threatened to seriously impede its further acceptance.