LOS ANGELES -- Whoever succeeds Alberto Gonzales as attorney general will face a long list of challenges at the Justice Department, from unfilled senior positions to sagging morale. One of the most pressing, according to dozens of current and former federal prosecutors, is a budget squeeze at U.S. attorneys' offices that has led to declines in crime prosecutions and delays in major investigations.

In the past few years, U.S. attorneys' offices around the country have been unable to fill vacancies. Lawyers sometimes can't travel...