THEN THE CARTER administration announced its selection last summer of Norval Morris to run the Law Enforcement Assistance Administration, there was suddenly hope for that agency -- some reason to believe that it might be turned into a more constructive arm of government. Mr. Morris, dean of the University of Chicago's law school, has the credentials and the ability to provide LEAA with first-class leadership, something it has lacked during most of its decade-long existence. But now the nomination of Mr. Morris has been withdrawn. And that tells you a lost about what is wrong with LEAA.

Mr. Morris has two grievous liabilites, according to those who opposed his nomination. He advocates strict gun controls, and he favors removing the criminal penalties for victimelss crimes, like public drunkenness, use of drugs, abortion, gambling and various sex acts between consenting adults. Those who have different views on those subjects -- like the National Rifle Association -- raised enough of a rumpus on Capitol Hill last fall to block Senate confirmation of his nomination. Their opposition has now convinced both Mr. Morris and the Department of Justice that, even if he could be confirmed next year, his usefulness as LEAA's boss has already been undermined.

The message is clear: LEAA, whose mission is to improve the quality of law enforcement across the nation, is still the special province of those who define improvement primarily in terms of catching more criminals. It was that mentality that led LEAA in its early years to spend millions of dollars buying new hardware -- guns, helicopters, tanks -- for police department, while spending relatively little on such endeavors as an all-out attack on juvenile delinquency, which might make a difference in the number of crimes committed. The basic objection to Mr. Morris appears to be that he threatened to change LEAA's course -- in what we would view as a sound and sensible way.

This does not bode well for President Carter's efforts to redirect LEAA's operations. Even if the administration's proposed legislation is passed in substantially the form in which it was sent to Congress last summer, LEAA will need a director of Mr. Morris' stature and vision to make the new approach work. Given what has happened to his nomination, the administration will be hard put to find another equally qualified administrator. And even if it could do so, the political strength demonstrated by Mr. Morris' opponents makes you wonder whether LEAA has a future as an effective agency. Perhaps the administration ought to consider going back to its inclination when President Carter frist took office, which was to tell Congress that LEAA should be abolished if it is not going to be allowed to fulfill its original purposes.