At the time, Republicans seized on Northam’s words to accuse Democrats of supporting infanticide. In a barrage of legislative propaganda, they put forward laws meant to prohibit murderous behavior of the sort Trump described, which is, of course, already illegal. The point of these proposals isn’t to right an existing wrong, but to put Democrats in a no-win situation. To vote in favor of them is to concede the premise that the bills address something real. To oppose them is to be accused of tolerating baby killing.

It’s tempting to ignore the president’s mendacity, since, as with so much of Trump’s malicious propaganda, it’s hard to counter it without amplifying it. Trump’s lies work to focus public attention on issues of his choosing; if Democrats are trying to explain that they don’t support infanticide, Trump has already won.

But leaving the lie unchallenged is also dangerous. Abortion providers are regular targets of domestic terrorism, and Trump’s lies serve as incitement. In 2016, a man fired an AR-15 inside a Washington pizzeria because he believed right-wing conspiracy theories that it was the epicenter of a child sex trafficking ring involving Hillary Clinton. Now the putative leader of the free world is spreading tales about unimaginable Democratic depravity toward innocent children.

It’s not a stretch to imagine an unstable Trump acolyte taking him both seriously and literally. Indeed, it seems that at least one already has. Last week, a 30-year-old Trump supporter named Matthew Haviland was arrested and accused of threatening to rape and murder a professor who supports abortion rights. According to an affidavit by an F.B.I. joint terrorism task force officer, Haviland wrote in an email, “I will kill every Democrat in the world so we never more have to have our babies brutally murdered by you absolute terrorists.” He also made over a hundred threatening calls to an abortion clinic.

Besides their potential to inspire violence, Trump’s words are a cruel insult to parents who have to make agonizing decisions about end-of-life care for babies that are born extremely prematurely, or with serious anomalies. Doctors and mothers don’t choose to “execute” newborns. They are forced to decide, in excruciating situations, when to forgo medical interventions and provide palliative care instead. There are exceedingly rare cases where babies survive an attempted abortion, but federal law already extends the same protection to them due any other infant.