The attack in Nigeria is part of a global backlash against girls’ education by extremists. The Pakistani Taliban shot Malala Yousafzai in the head at age 15 because she advocated for girls’ education. Extremists threw acid in the faces of girls walking to school in Afghanistan. And in Nigeria, militants destroyed 50 schools last year alone.

If the girls aren’t rescued, “no parent will allow their female child to go to school,” Hadiza Bala Usman, who has led protests in Nigeria on behalf of the missing girls, warned in a telephone interview.

Northern Nigeria is a deeply conservative area, and if the schoolgirls are recovered, it may be difficult for them to marry because of suspicions that they are no longer virgins.

While the Nigerian military has shown little interest in rescuing the girls, it has, in the last few years, presided over a brutal counterinsurgency in response to Boko Haram bombings. There is viciousness on both sides.