Advocates for changing the voting method for city offices in St. Paul won't sue after the City Council declined to put a petition-driven question on the November ballot.

The group, FairVote Minnesota, now plans to intervene as a defendant in a lawsuit challenging the constitutionality of instant-runoff voting in Minneapolis, where voters approved the ranked-choice voting system in 2006.

The Better Ballot Campaign, an arm of FairVote that pushed the voting system in St. Paul, said a month ago that it would likely sue if people weren't allowed to cast their vote on the issue.

More than 5,300 people signed a petition to put instant-runoff voting, which allows voters to rank candidates in order of preference, on the ballot.

The council voted 5-1 to keep it off the ballot.

It's a controversial method, and prevailing council members -- following the advice of City Attorney John Choi -- said it would probably violate the state's constitution.

The Better Ballot Campaign said it is not the council's role to decide what is or isn't constitutional. It would have sued to get a court interpretation of the method's constitutionality but decided that that wouldn't produce a decision in time to educate voters before the fall election.

The St. Paul Council also passed a resolution that would put the question on the ballot if the method were deemed constitutional in the Minneapolis case.

Choi said he's glad the instant-runoff supporters agree with the position of waiting to get a ruling in the Minneapolis case before pursuing action in St. Paul.