When they vote on Measure M this fall, Menlo Park residents will be participating in what may be the most consequential ballot-box decision ever made regarding the future character of their community. One of the most complicated as well.

The ballot measure sprouted from the frustration of some residents -- many of whom have been active in city governance and community service for years -- over the City Council's decision last year not to adjust several provisions of the new downtown specific plan. The residents say those provisions have created loopholes for developers, allowing them to build projects that don't live up to the community's vision for the downtown -- a vision that was forged during years of public meetings and workshops.

Of primary concern to those residents was a provision that set the project-size threshold for triggering public benefit requirements far higher than it had been before the new specific plan was approved the previous year. The unhappy residents pushed hard to change that rule, calling it a give-away to developers planning projects along El Camino Real. Although the council made a few changes to the plan, including reducing the amount of allowable medical office space, it didn't budge on the public-benefit trigger and other provisions of concern.

Citing new proposals that many residents believe have too much office space -- one by Stanford for its 8-acre property on the southern end of El Camino and another by Greenheart for a 7-acre project near the northern end -- the dissatisfied residents launched a successful signature-gathering campaign to put a measure on the ballot. The measure, among other things, sets a conservative cap on office space in the specific plan area -- a move they say is needed to stem peak-hour traffic gridlock and ensure balanced development along the El Camino.

Voters who generally favor the Stanford and Greenheart proposals, which are works in progress as the plans go through the normal approval process and the city negotiates for non-mandatory public benefits, have a clear choice on Measure M. They will vote no.

But the key question for residents opposed to the developments as proposed is this: Will Measure M address your concerns over increased traffic and building mass along the El Camino corridor? The answer, in our opinion, is no. Measure M's provisions fall short of achieving the intended goals -- goals that we and many other of the measure's opponents are sympathetic to. A curious omission in the measure pertains to the up-zoning in the specific plan that raised the public-benefit threshold. Measure M doesn't address that at all, even though that issue, and the council's unwillingness to deal with it, provided much fuel for the citizen action that led to the ballot measure.

The measure requires a vote of the people to change any of its provisions, which include key definitions and the problematically worded ban on the adoption by the city of "any new provisions or amendments to the Policy Planning Documents that would be inconsistent with or frustrate the implementation" of the measure's rules. Such ambiguous language is a recipe for litigation. It also could discourage other developers of potentially desirable projects from even trying to navigate the process of getting a plan approved in Menlo Park.

Opponents call Measure M "ballot-box zoning," but that's a reach. If most residents agree that office space shouldn't squeeze out other uses on El Camino Real but believe the council is going to thwart that vision by approving massive office projects under consideration, a ballot measure can be a reasonable, democratic strategy. But Measure M is flawed, and is not the right tool to fix what proponents want fixed.

If the measure fails at the ballot box, however, city officials would be wrong to interpret its defeat as an endorsement of the more than 800,000 square feet of development that has been proposed. Even Measure M opponents have publicly criticized aspects of the specific plan that don't give the city the muscle it needs to effectively negotiate public benefits when major projects are proposed. These include Planning Commission chair Ben Eiref, who in a guest opinion in last week's Almanac noted that a lower public-benefit trigger in the specific plan would be "the ultimate source of control" over large projects.

Planning Commissioner John Kadvany, who says he is critical of Measure M but hasn't publicly taken a position on it, said at last week's commission meeting that the decision not to lower the trigger threshold was "the biggest mistake the council has made in the last couple of years."

We agree with those comments, and hope that, should Measure M fail, proponents -- and those who opposed it because they believe it's the wrong tool to address legitimate concerns -- will turn their energy toward pushing the council to do the right thing. The council needs to lower the public-benefit threshold on projects, and soon, while there's still time for such a change to affect what gets built in the Stanford and Greenheart projects.