It was one of the opening night’s most dramatic and sober moments. Three women emerged on the main stage, each in a spotlight against the darkness.

Amanda Zurawski, standing beside her husband, told of how she nearly died when her baby would not survive and she could not get abortion care in Texas. Kaitlyn Joshua spoke of bleeding, miscarrying and being turned away from two emergency rooms in Louisiana. And Hadley Duvall of Kentucky told a harrowing story of being impregnated by her stepfather at age 12.

“He calls it ‘a beautiful thing,’” she said, quoting former President Donald J. Trump’s praise for states that have enacted strict abortion bans. “What is so beautiful about a child having to carry her parent’s child?”

Audible gasps punctured the silence of the arena. Women wiped away tears. Next to her husband, Gwen Walz shook her head in apparent horror, trying to take it all in. And when the testimonies were finished, the arena rose to its feet in support.

Such a scene was unimaginable at the Democratic National Convention just four years ago, when the word “abortion” was never mentioned on the main stage. Then, it was Republicans who embraced the issue at their party convention, awarding key speaking slots to anti-abortion activists and boasting of their “pro-life” bona fides.

But in the first presidential election without the foundation of Roe in half a century, the political scripts have been inverted. The decision in Dobbs v. Jackson Women’s Health Organization, which eliminated the constitutional right to an abortion, is one of Mr. Trump’s signature accomplishments — he appointed the three Supreme Court justices whose votes proved decisive. Detailed calls for federal limits on abortion have been a central plank of the Republican Party for decades.