Proponents of an initiative that would ban the manufacture of nuclear weapons in Cambridge won one legal battle this week, but the ultimate fate of their proposed referendum is still unclear.

The state ballot law commission ruled Tuesday that it did not have the jurisdiction to rule on objections to the referendum raised by employees at Charles Stark Draper Laboratories, a firm that would be severely affected by the measure. Draper employees had challenged the validity of some of the petition signatures supporting the measure.

Laura A. Carroll, a Draper attorney said earlier this week that her clients would not appeal that decisions, however, because they felt the referendum had been effectively blocked by the Cambridge City Council.

On Monday night, the council failed to pass a motion that would place the binding Nuclear Free Cambridge question on the November ballot. The two sides differ on whether the council actually has the power to keep an initiative off the ballot, and the likely outcome, some observers say, is that the proponents will have to sue the council to keep the referendum alive.

Carrol, cutting earlier court cases, said that municipal bodies have the power on keep initiatives off the ballot if they consider the aim illegal of unconstitutional as many have said of the current initiative.

But a recent advisory memo from the Massachusetts Secretary of State's office said that a city council cannot refuse to submit an initiative petition to the electorate if it believes the measure to be unconstitutional. "The note added that the council's duty to place something on its ballot is a ministerial one, with no discretion.

Cambridge City Manager Robert W. Healy who will reportedly make the initial judgment on the council's vote did not return repeated phone calls yesterday.