"The lesson is never write a book."

Norval Morris, dean of the University of Chicago law school and President Carter's choice to head the Law Enforcement Assistance Administration, was smiling when he said that at his Senate confirmation hearing yesterday.

But there must have been times during the three-hour opening session when the 55-year-old Morris wondered why he ever wrote "The Honest Politican's Guide to Crime Control."

For the 1970 book that he co-authored advocates - often with a tongue-in-cheek style - everything from gue control to decriminalizing gambling, drug offenses and all manner of adult sexual behavior.

Yesterday the National Rifle Assocation and a number of senators weren't laughing.

The gun lobby has mounted a full-scale offensive against the nomination. And five weeks before an election, politicans faced with a compilation of Morris's outspoken views are hard pressed to ignore them.

Several Democrats on the Senate Judiciary Committee seemed to be evaded the confrontation yesterday by their absence. Freshman Republican Orrin G. Hatch, of Utah, ended up chairing the session, though Sen. Edward M. Kennedy (D-Mass.), the next Committee chairman, did appear - despite what appeared to be a painful back - to speak for Marris.

Sen. Strom Thurmond, of South Carolina, the ranking committee Republicans, began the hearing by reading Morris a long list of quotes from his writings, which the NRA had compiled.

And Sen. Jesse Helms (R-N.C.), while not a member of the committee, put out a press release promising to filibuster the nomination if it reaches the Senate floor.

Morris tried to explain that his 1970 book had been written "to offer utopian views" and admitted several times that some of his points were "stupid simplifications" or "inept overstatements."

He amended his published view on "domestic disarmament" to say he was referring only to handguns. He said his comments about unarmed police were impractical for now, and were "rather science fiction."

Morris said his statement that "there can be no right of privacy in regard to armament" was "and author's aberration, and overstatement. I hope you forgive me for it."

And of his belief of cutting half the cases from juvenile court, he said. "I've written too much. Let me delete that."

The point of his writings, he said, was to suggest that law enforcement agencies concentrate their resources on violent crime and stop chasing vagrants, drunks, gamblers and homosexuals.

Morris hastened to point out that he would not try to impose his personal views on LEAA, the agency which has spent $6 billion over the past decade to help state and local authorities fight crime.

Hatch challenged that statement, saying, "I think it's unrealistic for you to say your policies wouldn't be pushed."

Morris responded that he was not on a crusade, and added: "I obviously come with a package of views. You don't want a moral neuter in the job."

Hatch said - echoing an NRA position - that he was concerned Morris might use his position to funnel LEAA grants to states with laws matching his beliefs. "That would be almost grounds for dismissal," Morris replied

The hearing continues today with questioning expected to focus on Morris' controversial views on drug offenses, according to Hatch. For instance, in answer to a question by Sen. Dennis DeConcini (D-Ariz.) yesterday, Morris said he would support pilot programs for heroin maintenance in the United States "if they are critically evaluated."

Morris noted ruefully near the end of yesterday's hearing that, if confirmed, he might impose "a moratorium on the greater spreading of my views."

Committee sources said it is possible that the Morris confirmation vote will be held over until January because of the controversy surrounding it. President Carter could then appoint him temporary LEAA administrator during the congressional recess.