Abortion roiled the midterms. Now it will define the presidential race.

Donald Trump delivered the Supreme Court majority that voted to overturn Roe v. Wade, signed a laundry list of executive actions that chipped away at abortion access and openly embraced the anti-abortion movement, becoming the first sitting president to appear in person at the annual March for Life in 2020.

Yet the response from anti-abortion groups when he announced his 2024 presidential campaign was, in more careful and polite terms: Take a number.

“We look forward to President Trump and all presidential contenders outlining their pro-life vision and policy platform in...