District voters yesterday gave overwhelming approval to a proposal requiring mandatory minimum prison terms for most crimes involving guns and for certain drug offenses.

In complete, unofficial returns from the city's 137 precincts early this morning, the tally was 70,037 for the measure, called Initiative 9, and 26,177 opposed, or 73 percent to 27 percent.

D.C. City Council member and unsuccessful mayoral candidate John Ray (D-At Large), who helped draft the proposed law, said last night the vote showed the "citizens understood that the intiative was needed and made sense. The citizens are probably 10 to 15 years ahead of the politicians on this one," Ray said.

Ray said the city's voters are "far more intelligent than we give them credit for," adding that "we the politicians have all allowed crime to get out of hand."

Former D.C. police chief Burtell Jefferson, who lobbied for the initiative as the chairman of Citizens for Safer Streets, said the strong voter support for the proposal "was a message to those persons committing crimes that they can expect swift and certain punishment."

Jefferson left his job as Ray's campaign manager to work full time on passage of the initiative.

If the final count shows that a majority of the voters support the proposed new law, it will be sent to Congress for review, as is the case with all routine District legislation.

If Congress takes no action within 30 days, the measure will become law.

U.S. Attorney Stanley S. Harris, the city's top prosecutor and an opponent of the measure, said his office would work with Ray to "fine-tune the provision to end up with the best possible result."

The U.S. attorney's office had said the measure would conflict with existing sentencing laws and interfere with the plea-bargaining process, by which many criminal cases are settled without trial.

Harris said he thought the strong voter support for the measure showed that "the community has a perception that there are people out there on the streets that shouldn't be there."

Opponents of the measure said last night that the lopsided vote in favor of the initiative showed that voters were anxious to vent their frustrations about the city's crime problem but were either unaware of or unconvinced by arguments that the new law would clog up the court system and not deter crime.

The Rev. Edward Hailes, president of Citizens for Sensible Sentencing, a coalition opposed to the measure, said last night that the vote was "evidence of the high level of public panic and impatience and frustration with crime in our city and not a total embrace of the mandatory minimum sentencing concept."

Leslie Harris, executive director of the Washington chapter of the American Civil Liberties Union, which also opposed the intiative, said it appeared to her that "people were voting on their emotions for what they think this bill is going to do.

"What it really was was an anticrime vote, not necessarily a mandatory sentencing vote," Harris said.

A spokesman for the National Rifle Association, which publicly lent its support to the measure in the final days of the campaign, said last night that the vote reflected the views of a cross-section of Disrict residents "who are very tired of miscreants committing violent crime."

John Aquilino, the NRA's director of public education, said that the mandatory sentencing law was a reasonable approach to the crime problem, as opposed to the District's current gun control law, which the NRA opposes.

Responsible gun owners, Aquilino said, "are not the people who commit crimes."

All District voters were eligible to vote for or against the initiative yesterday, regardless of party affiliation.

The initiative requires judges to impose a mandatory minimum prison sentence of five years for persons convicted for the first time of using a gun in the commission of a crime of violence.

A second such offense would carry a minimum term of 10 years, with no chance of probation or parole before that time had been served.

It sets out a mandatory minimum sentence of four years in jail for persons convicted of selling narcotic drugs such as heroin and 20 months for selling non-narcotic drugs such as phencyclidine or cocaine.

Sale of other controlled substances, such as marijuana, would carry a minimum term of one year if the drugs to be sold were valued at more than $15,000.

Persons under 22, who are eligible to be sentenced under the federal Youth Corrections Act, would not be subject to the mandatory sentences. The mandatory sentences can also be avoided for drug crimes if a first offender can prove he is an addict and sold drugs to support his habit.

Thirty-two states have adopted some form of mandatory sentencing, a concept that has become increasingly popular and controversial as communities have sought new and tougher ways to deal with crime and punishment.

A 1979 study in Michigan, which has a mandatory sentencing law for firearm offenses, showed that not only did 90 percent of the citizens surveyed support the measure, 65 percent said they would favor it even if they knew such laws did not help deter crime.

The initiative was placed on the ballot here after Ray and other supporters of the measure collected more than 24,000 citizens' signatures on petitions calling for a vote on the question.

It is the ninth initiative proposal since voters in 1978 approved the procedure for considering such measures.

A substantial list of opponents came out against the mandatory sentencing measure, including Harris, Del. Walter E. Fauntroy (D-D.C.), the local chapters of the NAACP and the Urban League and the League of Women Voters.

There were few visible supporters other than Ray, Jefferson and the NRA. But that side of the campaign got a sizable boost two weeks ago when an Associated Press/WRC poll showed that 71 percent of the city's registered voters supported the measure, 17 percent opposed it and 12 percent were undecided.

In the closing days of the campaign, the opposition organization seemed to lose what momentum it once had while Ray and his supporters walked from one slaying site in the city to another, urging support for the measure.

The campaign for and against the measure was decidedly low-budget, with expenditures totaling only about $5,000 for both sides, compared with a $135,000 campaign mounted unsuccessfully last year by backers of an education tax credit proposal.

There was, however, a stiff debate about exactly what implementation of the initiative could cost the city. Opponents argued it would overcrowd already strained prison facilities and sharply increase the cost of running the prison system, while proponents said projections of new inmates were greatly exaggerated.

Jefferson and other supporters of the measure, including the D.C. police labor committee, argued that if the initiative passed, the city would find the money to pay for it.

They said the narrow focus of the initiative would limit the number of persons jailed under it.

Opponents argued that the initiative would drain needed money away from other anti-crime efforts, like neighborhood crime watches, and from schools, job-training programs and drug treatment centers, which help counter the root causes of crime.