It's hard to blame William J. Bennett for deciding to step down as the nation's first drug czar after less than two years on the job. After all, the job generates not only controversy but also plenty of physical threats. And it isn't easy to make inroads in drug abuse. So early burnout can be expected in Bennett's successors.

Even so, Bennett might have chosen a less awkward time to depart - though changes in command at this sensitive post may never be easy. Right now, the drug war is at a crucial juncture. Though middle-class Americans finally seem to have realized that drug abuse is anything but smart and sophisticated, the problem seems to be increasingly serious among the poor in the nation's big inner cities.At the same time, Congress still is in love with the deceptively attractive idea that increased treatment is the cure for drug abuse. Never mind the appallingly high rate of failures and repeat offenses among so-called graduates of treatment programs. Never mind either the large numbers of drug abusers who drop out of such programs without ever completing them.

But then treatment is bound to keep looking attractive as long as drug-related crimes keep soaring even though tougher law enforcement is producing more crowding in the nation's courts and jails.

As Bennett steps down from the demanding task of coordinating the work of more than 30 federal agencies, he deserves mixed marks for his efforts. On the plus side, he produced the first comprehensive federal drug strategy. Unhappily, he prodded Congress to unleash the Pentagon in the war on drugs even though the military is not suited or trained for that task. But then Congress didn't provide the drug czar with enough money for much muscle. The $3.5 million budget for Bennett's office is less money than the Pentagon spends in only six minutes.

By conservative estimates, drug abuse costs the nation $53.8 billion a year in terms of lower productivity, treatment, crime losses, and law enforcement costs. The tab for the most abused drug of all - alcohol - comes to another $85.8 billion.

Keep those yardsticks in mind when the time comes to measure the accomplishments of whoever is bold and gritty enough to pick up where William Bennett left off.