We don't tell people HOW to vote, but we do start a phone chain encouraging people to get out there and vote. We also purchase signs "Vote Today on School Budget" and put them all over town.

This is a "hot topic!" I totally agree with your PTO President in her refusal of supporting the referendum drive. Our district is also expecting a referendum due to the large influx of housing developments.
At the beginning of the school year, our PTN Board received a visit from a few of our District School Board members informing us of an upcoming referendum. Knowing that our PTN could be a great utilization tool for "volunteer resources" in the community, they requested the help of parents who might consider hosting informal, "coffee club" referendum discussions. They did not put any of the members on the spot or request PTN support or funding. They just wanted to get the "buzz" going throughout the district.
As a whole, a PTN Board is comprised of parents of a particular school district. As a parent on the PTN Board and a registered voter in the district, I would be very angry if a small PTN group could motion funds or otherwise to support what I believe is a "personal choice." Not unlike a charity, my belief is that if I can somehow help the cause, as an individual I can always raise my hand!

If you look under Free for All, this was discussed. PTO/school referendum. Maybe you can get some ideas from there.

This March, our school board is going out for a building bond referendum to build new buildings to house a large influx of students due to many new subdivisions being built within our boundaries. There is considerable conflict between several PTO board members and other members at large regarding whether or not the PTO can lend support either financially or in other ways to the referendum process. The PTO president is adamant in her refusal of the PTO to participate in any way in the referendum drive - she feels that the PTO cannot be a part of this "political process". Many of our school's PTO members, however, want to do whatever we can to support our school board, our referendum committee and ultimately the children of our district by promoting the building referendum. We are also aware that other local PTO organizations in the surrounding area school districts have been and are currently making donations, furnishing volunteers, generating publicity and completely supporting their referendum committee and their district initiatives. Is it appropriate for the PTO to participate in this endeavor?