Democrats headed into the election hoping that abortion rights initiatives would drive support for Kamala Harris in states where the measures appeared on the ballot, including two presidential swing states, Arizona and Nevada.

But while the ballot measures, broadly put, performed well on Tuesday, succeeding in seven out of 10 states, Ms. Harris and other Democrats underperformed them across the map.

In both Arizona and Nevada, more than 60 percent of voters approved measures to enshrine abortion rights in their state constitutions, though more votes remained to be counted on Thursday. But Donald J. Trump appeared on track to win both states, according to New York Times estimates. Abortion rights initiatives also passed in Missouri and Montana, two states Mr. Trump won easily.

Even as a growing share of women said abortion access was central to their vote, pre-election polling suggested that it wasn’t voters’ top concern overall. Fifteen percent of likely voters in an October national New York Times/Siena College poll said abortion was the most important issue in their vote for president, but roughly twice as many listed the economy, or inflation.

The voters who cited abortion as their top concern favored Ms. Harris, 88 percent to 11 percent, and the voters who prioritized economic issues favored Mr. Trump, 72 percent to 24 percent.

In states where the ballot measures passed but Mr. Trump won or was leading, voters had, in effect, split their tickets, supporting abortion rights in their states while also backing a candidate who took credit for overturning Roe v. Wade, which had established a nationwide right to abortion. Ms. Harris had made protecting abortion rights a central theme of her campaign.