The ferocity with which Richard Nixon and Henry Kissinger bombed Cambodia, along with the desire to inflict extreme pain on North Vietnam, had a number of motivations. Some were explicit — to wring concessions out of Hanoi; to disrupt the National Liberation Front’s supply and command-and-control lines — and others implicit — to best bureaucratic rivals; to look tough and prove loyalty; to appease the Right.

“Savage was a word that was used again and again” in discussing what needed to be done in Southeast Asia, recalled one of Kissinger’s aides, “a savage unremitting blow on North Vietnam to bring them around.”

But there’s another way to think about the savagery, along with the wild, off-the-books way their air assault was carried out.