In little more than a month, a half-million Rohingya Muslims in Myanmar’s Rakhine state have been forced into a terrified exodus to Bangladesh. They fled the Myanmar military, which burned villages and reportedly shot men, women and children in retaliation for an attack on 30 police posts by a Rohingya militant group.

The scorched-earth campaign against the Rohingya has been called a “textbook example of ethnic cleansing” by the U.N. high commissioner for human rights, Zeid Ra’ad al-Hussein. An urgent, stern and unmistakable response is necessary.

The de facto leader of Myanmar, Aung San Suu Kyi, has been justifiably criticized for failing to find her voice, the eloquence of a Nobel Peace Prize laureate, during this brutal crackdown. But the chief perpetrators are in the military, with whom she shares power.

The army was undoubtedly furious over the militant attacks on police posts Aug. 25, but the subsequent response was entirely disproportionate, another chapter in the long and painful persecution of the Rohingya in Buddhist-majority Myanmar. Any response must now make clear to military leaders that inflicting such misery is intolerable.

More Rohingya are now in Bangladesh than in Myanmar. Failing to respond to their plight and persecution would compound the crime of their expulsion.