With Michigan set to vote next month on a ballot measure that would enshrine abortion rights in the state constitution, antiabortion forces have recently flooded the airwaves with more than $13 million worth of negative ads — outspending pro-choice groups in the state by nearly two to one. Abortion opponents will spend more than $21 million on TV ads by Election Day, according to advertising data from AdImpact.

Amid the onslaught, the abortion ballot measure’s polling numbers have remained strong, with 62 percent of voters now saying they support Proposal 3, compared to 24 percent who oppose the initiative, according to a new Detroit News survey. Roughly two-thirds of voters say they oppose the Supreme Court’s decision to overturn its landmark ruling in Roe v. Wade and invalidate federal protections for abortion rights.

A separate CBS News poll found that 54 percent of likely voters support the Michigan abortion initiative, with 38 percent opposed.