Arizona teachers plan more walk-ins as a Thursday strike looms.
New Effort Aims To Ban 'Dark Money' In Arizona Elections
Arizona voters may be asked next November to change the state Constitution, to outlaw so-called "dark money."
Former Attorney General Terry Goddard is leading the effort to put the issue on the 2018 ballot.
Goddard's group will have to collect more than 225,000 valid signatures by next July.