Gov. Doug Ducey has signed legislation banning cities and towns from requiring groups that spend money in elections from being required to disclosure their donors.
The proposal signed Thursday could essentially gut a new Tempe law approved by 91 percent of the voters requiring nonprofits that spend more than $1,000 in local elections to reveal their donors.
The measure passed the Senate and House with no Democratic support. Democrats argued that voters deserve to know who is funding political advertising in elections.
Republicans argued that anonymous political speech principals demand that groups be allowed to weigh in without their donors being harassed.
Voters approved the Tempe measure on March 13.