“Hamas cannot be wished away, nor will it cooperate in its own demise,” Carter writes, along with Mary Robinson, in a Foreign Policy op-ed Tuesday. “Only by recognizing its legitimacy as a political actor — one that represents a substantial portion of the Palestinian people — can the West begin to provide the right incentives for Hamas to lay down its weapons.”

Also in the op-ed, Carter faults Israel for stonewalling multilateral attempts at peace and for dangerously isolating Palestinians in Gaza, saying the “necessary requirements for a human standard of living continue to be denied.” And though he accuses both Israel and Hamas of committing war crimes through their “deliberate” attacks on civilians, he reserves his strongest criticisms for the IDF.

“There is no humane or legal justification for the way the Israeli Defense Forces are conducting this war,” he writes.