Can abortion ballot measures generate electoral spillover effects, and for whom? We exploit the geography of US media markets to isolate the effects of abortion ballot measures in 2022 and 2024 from related television advertising. We find that abortion ballot measures decreased the Republican vote margin in US House elections by 4.8 percentage points in 2022 but increased the margin by 4 percentage points in 2024. We discuss how these contrasting results can be explained by two mechanisms: a decrease in turnout in ballot states in 2024 and vote switching in 2024 such that voters separated their opinion on abortion from their choice of partisan candidate. We also provide the first evidence on the process via which abortion measures appear on the ballot: counties that have lost access to abortion providers in the prior year contribute more signatures towards ballot measure petitions.