A picture taken on March 4, 2015 shows a Syrian woman walking past a poster bearing a portrait of Syrian President Bashar al-Assad in the capital, Damascus. (Louai Beshara/AFP/Getty Images)

FOUR YEARS ago this week people across Syria began marching peacefully to demand democratic reforms. The country they sought to improve literally no longer exists. In death, destruction, refugees and sheer horror, Syria’s war outstrips any other of this century. That it has faded from public attention reflects not an easing of the crisis, but an abdication by the United States and other powers of their commitments to prevent mass murder.

Since Bashar al-Assad’s regime first responded to the peaceful demonstrators with gunfire, 6 percent of the prewar population of 20 million have been killed or wounded, and another 23 percent have left the country — including 4 million who live as refugees, according to a U.N.-supported study released last week. Outside of Damascus, most major cities have been reduced to rubble; a study of satellite images shows that 83 percent of the country’s electric lighting has been eliminated.

Humanitarian groups attempting to serve the Syrians still in the country say the situation has grown worse since the United Nations Security Council passed resolutions last year meant to improve aid deliveries. The regime is still blockading areas it does not control, preventing the delivery of food and medical aid. It still regularly attacks those areas with “barrel bombs,” dropped from helicopters and filled with shrapnel or, occasionally, chlorine gas.

The Obama administration, which once proclaimed the prevention of genocide a national security priority, has not even pretended to have a strategy for Syria since the collapse of a peace conference in Geneva 13 months ago. Though it is recruiting and training a few thousand Syrians to fight the Islamic State, the administration refuses to commit itself even to defending them if they are attacked by the Assad regime — much less to helping them take the offensive against Damascus. Senior officials say the White House fears a hostile reaction from Iran, which has sent troops and militia forces to fight for the regime.

Secretary of State John F. Kerry created a stir over the weekend when he appeared to suggest that the administration is now open to negotiating with Mr. Assad. In fact, the administration long ago adopted the position that the regime could participate in a political settlement as long as Mr. Assad himself was not part of it. Mr. Kerry tacitly acknowledged, as he has many times before, that even that solution is unfeasible unless “there will be increased pressure on Assad.” But the United States will not apply that pressure; instead Mr. Kerry is still hoping that Russia and Iran will do it.

There is no reason to believe that they will. In that sense, Mr. Kerry’s statements reflected the administration’s real policy, which is to wash its hands of Syria while hoping it can separately strike a deal with Iran on its nuclear program and collaborate with it to defeat the Islamic State in Iraq. At best, Syria’s continued agony will be the price for progress elsewhere in the Middle East. More likely, the Assad regime’s unchecked slaughter will continue to destabilize the region.