(Oscilloscope Pictures)

After Tiller,” a lucid, even-tempered portrait of physicians who perform late-term abortions, exemplifies the crucial role documentaries have come to play in civic discourse, which is so often whipped into partisan fury and emotionalism. In between straight-up journalism and op-ed histrionics, nonfiction narrative films — when done as well as this one — fill in the spaces between the facts with human stories that have the power to change the way viewers think about an agonizing personal and political issue.

The title of “After Tiller” refers to George Tiller, a provider of late-term abortions who in 2009 was assassinated in Wichita, Kan. Since then, four of Tiller’s colleagues have taken up similar practices: two in New Mexico, one in Colorado and one, LeRoy Carhart, who in the course of “After Tiller” moves his office from Nebraska to suburban Maryland. They currently are the only providers of third-trimester abortions in the country.

It goes without saying that the procedure at the heart of “After Tiller” — wherein pregnancies are terminated in their third trimester, resulting in what is essentially the stillbirth of a premature infant — is at the center of a noisy, fast-moving national debate. But rather than focus on the shouting, filmmakers Martha Shane and Lana Wilson bring their cameras into the clinics themselves, where they intimately record medical professionals and their patients reaching agonizing decisions regarding the health and welfare of their would-be children, their families and themselves.

Far from the crass, exploitative murderers their opponents portray them as, the physicians in “After Tiller” emerge as thoughtful and dedicated — people who have come to their practices almost by accident but who have come to believe ever more strongly that women, as one doctor puts it, “are the world’s experts in their own lives.” More often than not, the reasons for a late-term abortion are medical, having to do with fetal abnormalities that would mean a short, painful life for the baby after delivery. But eventually, “After Tiller” gets around to the much gnarlier ethical questions of women who, for whatever reason, have simply put off their decisions, circumstances that the physicians and their staff members grapple with openly and thoughtfully.

Sometimes the answers are unsettling. Every audience member will determine at which point they agree or disagree. But “After Tiller” declines to judge, even when it comes to the demonstrators outside the clinics, who clearly have no idea of the compassion, moral inquiry and deep caring that is going on inside the place they’re picketing.

“After Tiller” does viewers the great service of providing light where there’s usually only heat, giving a human face and heart to what previously might have been an abstract issue or quickly scanned news item. No one wants to think about late-term abortion. But “After Tiller” gives us a language to do just that. With luck, the ensuing conversations can be as humane and carefully considered as the film that will surely inspire them.

★ ★ ★

PG-13. At West End Cinema. Contains mature thematic material involving abortion and brief strong profanity. 85 minutes.