More than 100,000 people have died in Syria’s two-year civil war. The brutal conflict became a crime against humanity long before the gas attack that killed 1,400 civilians. But it took the chemical weap­ons atrocity — and the threat of a U.S. military response — to focus the world’s attention.

As U.S. forces poised to strike, Christians who believe all war is a crime stood with a remarkably broad antiwar coalition. Pacifists and tea party conservatives, liberals and libertarians rose to say no to war.

All agreed the Syrian war is a moral crisis demanding a firm response. But, as U.S. peace advocates asserted and Middle Eastern Christians affirmed, escalating the war offered no solution to end Syrians’ suffering. And, as war-weary Americans of diverse political loyalties pointed out, acts of war require a high probability of achieving clear national-security goals.

For once, the American public and Congress greeted a president’s call to arms with skepticism. Some of the opposition surely reflected a decade’s hard lessons of war’s futility.

From the highest Christian pulpit came a call for peace: “I make a heartfelt appeal … to lay aside the futile pursuit of a military solution,” Pope Francis said. His words hit key points of the antiwar position: A military strike offers no hope of ending the killing and might even make things worse. A moral solution can only come through peaceful means.

Airstrikes meant to punish the regime of President Bashar al-Assad would do no good for the people of Syria. They would likely add to the civilian death toll and fail to end the use of poison gas. They would escalate the violence and risk a wider war with deeper U.S. involvement. Mennonite Central Committee declared: “Further militarization of the conflict will only increase the suffering of the Syrian people and the shattering of Syrian society.”

There is no good side to take in the Syrian war. A New York Times report described Syria’s “complex guerrilla and criminal landscape” where “American military action could inadvertently strengthen Islamic extremists and criminals.”

The choice in Syria is not between launching missiles and doing nothing. The tools of diplomacy and international condemnation remain far from exhausted. “The Middle East is an honor and shame culture,” wrote J. Daryl Byler, director of the Center for Justice and Peace­build­ing at Eastern Mennonite University, in the Richmond Times Dispatch. He called for broadly exposing the evidence of chemical warfare, using the stories of innocent children and civilians to place the full weight of the world’s judgment on the Syrian regime. An indictment by the International Criminal Court would intensify the pressure.

Hope for a diplomatic solution increased Sept. 10 when U.S. officials expressed qualified support for a Russian proposal requiring Syria to turn its chemical weapons over to international control. The Obama administration should abandon the threat of a military strike and work with the United Nations to negotiate an end to the war and the destruction of Syria’s chemical arsenal.