Hillary Clinton and Donald Trump clashed Monday night about partial-birth and late-term abortion. Judging by the media coverage of that exchange, there seems to be a fair amount of confusion about these subjects. I’ll try to dispel some of it.When partial-birth abortion happens: First, it’s worth keeping in mind that late-term and partial-birth abortions are two different, though related, subjects. Post-“viability” abortions were not always partial-birth abortions even when partial-birth abortions were generally legal, and partial-birth abortions sometimes took place before viability.Terminology: People who think partial-birth abortion should be legal sometimes sniff that “partial-birth abortion is not a medical term.” It is unclear why this should matter. It is a term defined in federal law, and its definition has not been struck down on grounds of vagueness. And as Kenneth Woodward pointed out when the New York Times refused to use the term in its reporting, to be consistent about a prohibition on non-medical terms it would also have to excise “heart attack” from its pages.The reasons partial-birth abortions are done: Clinton made it sound as though partial-birth abortions are usually done for health reasons. This claim was frequently advanced during the early days of the debate over partial-birth abortion. It is untrue. Check out this 1997 New York Times story, or just read the opening line: “A prominent member of the abortion rights movement said today that he lied in earlier statements when he said a controversial form of late-term abortion is rare and performed primarily to save the lives or fertility of women bearing severely malformed babies.”The frequency of partial-birth abortions and late-term abortions: NPR’s “fact check” of the debate links to a 2006 NPR story that says that partial-birth abortion, before it was banned, was performed “only” about 2,200 times a year. An NPR story specifically about last night’s abortion exchange said: “Only about 1.5 percent of abortions take place 20 weeks or later after conception. Of those, the vast majority happen before 24 weeks.” It also said that the number of partial-birth abortions “is believed to be small.”It is not clear why the number of partial-birth abortions should be thought relevant to the argument between Trump and Clinton. It is illegal under federal law except to save a mother’s life, and Clinton believes it should be available more widely. Describing the numbers involved as “small” is also tendentious. The Alan Guttmacher Institute reports that in 2011, 1.06 million abortions were performed in the U.S. Using the 1.5 percent estimate would mean that there were 15,900 abortions after the 20th week. AGI also reported (as noted here) that there were 2,200 partial-birth abortions in 2000, when it was generally legal. Are these numbers small? Douglas Johnson of the National Right to Life Committee once pointed out that if a new virus was killing 2,200 premature infants in neonatal wards each year, it would be on the evening news every week. Note also that this estimate of the number of abortions after the 20th week exceeds the number of gun deaths in the U.S. last year. Does it seem to you that the press typically treats this as a small number?#related#Clinton’s stance: Many news outlets accused Trump of misrepresenting Clinton’s position by bringing up the possibility of killing “the baby on the ninth month on the final day.” This does not happen, said the fact-checkers. But go back and read the transcript: What Trump said (in two iterations) was that “if you go with what Hillary is saying in the ninth month you can take the baby and rip the baby out of the womb of the mother just prior to the birth of the baby.” That is the logic of her position on late-term abortion, which is that an abortionist should be free to perform an abortion at any stage of pregnancy if there is a health reason for it, including a reason of emotional health. Some journalists were touting this criticism of Trump’s comments and defense of Clinton’s position, which ends up saying that abortions at the very end of pregnancy never happen but should still be legal because of the principle of the thing. Trump grasps that logic and says he objects to it. “Now you can say that that’s okay and Hillary can say that that’s okay, but it’s not okay with me.” You can agree with Trump or you can agree with Clinton, but you can’t truthfully say that there’s no difference between their stated positions.— Ramesh Ponnuru is a senior editor at National Review.