President Obama quickly canceled an impending U.S.-Egpyt military exercise in the wake of the massacre Wednesday, in which Egyptian forces killed more than 500 protesters and wounded thousands more.

The killings demonstrated that Egyptian security forces, which ousted President Mohammed Morsi in July, would not hesitate to turn their might against mostly unarmed protesters in their zeal to suppress Islamist elements represented by Mr. Morsi's Muslim Brotherhood.

Islamists, in turn, lashed out against Coptic Christians, burning at least seven churches and attacking clergy and worshippers, as they had with near impunity during Mr. Morsi's tenure.

The Muslim Brotherhood proved during its year in office only that it was incapable of ruling democratically despite the democratic process that vaulted it from the shadows to power.

Meanwhile, the Obama administration has not called Mr. Morsi's ouster a coup because doing so, by law, would require it to suspend U.S. aid to the Egyptian Army.

After the security forces' rampage, it is clear that no one wielding power in Cairo will do so democratically.

The U.S. has a strategic interest in providing military aid to Egypt. It's the currency of influence that has helped to maintain the peace between Egypt and Israel.

Now, however, the United States should not provide aid that is misused as it was Wednesday. Doing so only worsens American standing in the Middle East.

The Obama administration should suspend the aid.