Attitudes on abortion are deeply entrenched and have motivated voters across the American political landscape for decades. But in a post-Roe world, with abortion access sharply limited or at stake in several states, voters who want to protect abortion rights are increasingly energized.

Although the economy remains the No. 1 issue for voters, a growing share of voters in swing states now say abortion is central to their decision this fall, according to New York Times/Siena College polls earlier this month. This represents an increase since May, when President Joe Biden was still the Democratic presidential nominee. And by a wide margin, more say they trust Vice President Kamala Harris over former President Donald J. Trump to handle abortion.

Mr. Trump has repeatedly changed his position on the issue, despite appointing Supreme Court justices who voted to overturn Roe v. Wade, the 1973 case that found a constitutional right to abortion.

On Thursday, he even suggested that he might support a Florida ballot measure that would expand abortion rights — which he and his campaign quickly tried to walk back. But his shifting stance may reflect hope among Democrats, and concern among Republicans, that backlash to abortion restrictions may drive voters to the polls.

That may be especially the case for women — particularly now that Kamala Harris is at the top of the Democratic ticket.