PRESIDENT OBAMA has adopted the position that any U.S. intervention in Syria would be ineffective, “short of us being willing to undertake an effort in size and scope similar to what we did in Iraq.” His aides regularly accuse those who critique U.S. policy — which currently consists of donations of humanitarian aid and a feckless attempt to promote peace negotiations — of favoring another Middle East war.

In reality, the United States has a number of options for action in Syria that would be more robust than the current policy but fall well short of the use of U.S. ground forces. They might not bring the Syrian civil war to a quick end, but they could address several major challenges, including the horrific war crimes being committed by the regime of Bashar al-Assad, the dire humanitarian crisis affecting several parts of the country and the growing power of Islamic extremist forces.

The first and simplest step would be for the Obama administration to back a resolution being developed by Britain and other allies in the U.N. Security Council. It would call for allowing humanitarian aid deliveries to areas now cut off because of military sieges and authorize U.N. agencies to work in areas not under government control. More than 200,000 people in the Damascus suburbs and the city of Homs are being deliberately starved of food and medicine by government forces, which is a war crime. The Security Council — in particular, regime defenders such as Russia — should be forced to cast a vote for or against ending this abomination.

Whether the resolution is approved or not, the Obama administration could take action to end the blockades and other crimes, such as the regime’s ongoing practice of dropping “barrel bombs” from helicopters on civilian housing, hospitals and schools. These weapons are filled with nails, pieces of metal and other junk intended to inflict maximum damage on civilians. The administration could inform the Assad regime and Russia that if the atrocities do not stop, Mr. Obama will order missile strikes against facilities that carry out and support them, such as helicopter bases. Given the regime’s reaction when Mr. Obama threatened such action last summer, it might relent; if not, its ability to bomb and blockade could be significantly degraded.

Mr. Obama has disparaged the al-Qaeda threat in Syria, calling it a “JV team.” U.S. intelligence agencies apparently disagree. Last week the director of national intelligence, James R. Clapper Jr., told Congress that Syrian al-Qaeda forces aspired to carry out attacks against the U.S. homeland and compared the areas under the terrorists’ control to Pakistan’s tribal territories.

Mr. Obama could address this threat by returning to a plan he embraced and then dropped last year: accelerating the arming and training of moderate opposition forces. The administration’s exaggerated emphasis on the failing Geneva peace talks has obscured the reality that fighting on the ground is likely to determine Syria’s near-term future as well as any eventual settlement. Russia, Iran and Saudi Arabia are backing various Syrian forces; the United States and its allies should train and equip their own allies, which would battle al-Qaeda as well as the regime.

U.S. inaction over the past three years has left the administration with more difficult options. But options still exist. It is not too late to stand against the regime’s atrocities and the growing terrorist threat.