DiIulio, a Democrat and academic, was regularly frustrated by the politics of Washington as he tried to steer the Bush initiative through Congress. He was also exhausted by his commute several times a week from Philadelphia, where he is on leave from the University of Pennsylvania.
His initiative was attacked by conservatives and liberals alike, who for different reasons opposed sending tax dollars to churches, synagogues and other religious groups.
Liberals opposed the initiative for fear that government would wind up paying for religious activity, breaching the constitutional separation between church and state.
Conservatives feared that government funding would lead to government intrusion on churches, and that tax dollars might wind up with non-mainstream religious groups.
DiIulio complained that critics were focusing on the extreme cases and ignoring the good work that religious people can accomplish. And he hit back directly at the conservative, evangelical critics, saying they do not speak for the entire religious community. "Predominantly white, exurban, evangelical and national parachurch leaders, should be careful not to presume to speak for any persons other than themselves and their own churches," he said in March. He is leaving at a critical time for the initiative.
DiIulio helped push legislation opening 10 government programs to religious groups through the House, but the measure faces a tougher time in the Senate. So far, no Democrat has been willing to sponsor the legislation, though Sen. Joe Lieberman, D-Conn., is working on a bill.
DiIulio, 43, will be the first high-profile Bush appointee to leave the administration. His job pays $140,000 per year.