Those initiatives are likely to draw some support from Republican voters. The POLITICO analysis of data from five states that have held abortion referendums since 2022 shows varied levels of crossover voting, with a decisive share of voters in some states backing both Republican candidates and abortion rights.

That underscores the ambiguity for 2024, when a handful of states will have abortion rights on the same ballot as GOP candidates who support abortion restrictions. And although abortion referendums drew relatively high turnout for off-year elections, 2024 is the first test of the phenomenon in a presidential election year, when millions of voters who sat on the sidelines for the referendums are expected to cast ballots.

In Ohio, Republicans made up a greater share of the vote in the
November 2023 abortion referendum than Democrats, according to a POLITICO analysis of voter records showing participation in partisan primaries over the last two years.

The geographic breakdown of votes in other states also did not indicate a surge in Democratic turnout.

In California, for example, 66.9 percent of voters approved a constitutional amendment to protect abortion rights in 2022 — more than 7 points ahead of Democratic Gov. Gavin Newsom’s reelection bid.

The measure succeeded in spite of low Democratic turnout: Turnout from 2020 to 2022 dropped the most in strong Democratic counties compared to Republican-inclined ones. Abortion rights still won big, driven by Republican crossover voters, but lower turnout among Democrats contributed to the party’s struggles down ballot.

The effect of the ballot measures is even murkier in red states.

In Kentucky, where voters rejected a referendum last year that would have denied constitutional protections for abortion, turnout in the state’s handful of blue counties was about 2.5 percentage points better than the rest of the state. But that slight bump was not enough to boost Democratic candidates — Sen. Rand Paul (R-Ky.) won reelection by 23 points.

The political impact, however, varies from state to state, and Democrats who insist the referendums can make a difference point to Michigan. Voters there enshrined abortion rights in their state constitution in 2022, handed Democrats the majority in both legislative chambers for the first time in decades and reelected Democrats Gov. Gretchen Whitmer and Attorney General Dana Nessel.

Jill Alper, the DNC’s former political director and a Michigan-based campaign consultant, pointed in particular to women outpacing men in voter registrations leading up to the vote and the surge in youth turnout — which increased in the state by
3.8 percentage points
even as it declined nationwide compared to the 2018 midterms.

“There was something real at work there,” she said. “People are seeing this as an issue of freedom versus government interference, and I think it was pretty important to Whitmer’s victory.”