OPPONENTS OF ABORTION in three New England towns proclaimed "moral victory" last week because they had gotten a hotly resisted referendum question -- "Should the Supreme Court decision regarding abortion be overturned?" -- on last Tuesday's ballots. Supporters of the referendum in all three towns -- Bristol, Conn., and Dover and Derry, New Hampshire -- billed it as a direct gauge of voter opinion on abortion, the first since the Court handed down Roe v. Wade in 1973. Patrick Mahoney, director of the Bristol- based Celebrate Life, hailed Bristol as "a test case for the nation" and talked of building a dramatic groundswell of grass-roots support for a constitutional amendment.

But something happened Tuesday to his "victory": the referenda failed. All three towns voted no, Dover and Derry with majorities of 65 and 60 percent, respectively, and Bristol more narrowly by 8,555 to 6,738. All three towns are heavily blue- collar and conservative, with large Catholic populations; Bristol's five local anti-abortion groups had particularly high hopes because Catholics make up 60 percent of the electorate.

But these voters reaffirmed Roe v. Wade -- and went even further. In Bristol, both mayoral candidates refused to state their positions on the issue publicly. In Dover, voters rejected the reelection bid of incumbent city council member Bucky Peters, who had first proposed the Dover referendum and pushed hard for it in a city council that eventually voted 5-4. And in Derry, Mary Ann Edman -- who opposes abortion and had led the petition drive for the referendum -- also lost her bid for a council seat.

In Bristol, the fight was long and heated; Celebrate Life entered a float with pictures of fetuses in the annual Bristol Mums Parade. The New Hampshire campaigns were shorter -- four to six weeks -- and copied the question's wording from Bristol, where it had been a compromise between the two sides. Opponents of the referendum, including local chapters of the National Organization for Women (NOW) and the National Abortion Rights Action League (NARAL), say they would rather not have fought the battle but that in some ways it advanced their cause. In New Hampshire, for instance, NARAL added 50 members and more than 150 volunteers to a statewide force of 900.

Celebrate Life and national anti-abortion groups still say they will push for expansion of the referendum tactic. They hope to place a Roe v. Wade question on hundreds of state and local ballots in 1986. They might do better to back off. Countless opinion polls support that they are in the minority. The New England results underline yet again that most Americans believe they should decide the tangled and painful matter of abortion for themselves.