Even in a presidential debate packed with shocking charges, the bombshell phrase stood out.

“Execute the baby.”

Donald J. Trump used that violent and false rhetoric on Tuesday night to attack Vice President Kamala Harris for her support of abortion rights, a tactic that he has employed for years to claim the moral high ground on a divisive issue. In his final 2016 presidential debate, he accused Hillary Clinton of wanting to “rip the baby out of the womb.” Earlier this year, he said President Joe Biden would legalize abortion rights to “kill the baby.”

There is no state in this country where it is legal to kill a baby after it’s born. But Mr. Trump’s rhetoric has served as a politically powerful tool to galvanize his socially conservative Christian supporters who saw it as a moral call to arms.

That was then. The fall of Roe v. Wade plunged the country into a visceral national conversation about abortion, miscarriage and birth. Women told their stories of facing life-threatening complications, and the emotional pain of losing wanted pregnancies. Health care providers discussed heartbreaking cases of girls being raped and impregnated.

During the debate, Ms. Harris used those personal stories to try to refute Mr. Trump’s old line on new grounds: His claim was not only false but immoral.

“A survivor of a crime, a violation to their body, does not have the right to make a decision about what happens to their body next,” Ms. Harris responded. “That is immoral. And one does not have to abandon their faith or deeply held beliefs to agree the government, and Donald Trump certainly, should not be telling a woman what to do with her body.”