A 14-year-old fighter in a Free Syrian Army brigade takes position inside a house in Deir al-Zor, a city in eastern Syria, in July 2013.

President Obama has the clout to get child soldiers off the battlefields in countries around the world. But he has been too reluctant to use it. As the fiscal year ended on Sept. 30, he gave some countries a pass to get U.S. military aid—in some cases millions of dollars – that he should have held back until they change their ways.

Congress passed a groundbreaking law in 2008 that prohibits the U.S. from giving several forms of military assistance to governments using child soldiers. Its intention was to use a powerful incentive – withholding US military training, funding, and weapons – to influence other governments to stop using children in their military forces.

The Obama administration knows that the tactic can work.  In the Democratic Republic of Congo, thousands of children have fought—and often died—on the front lines of the country’s many civil conflicts. In 2012, when the U.S. withheld millions of dollars in military financing and the training of a military battalion from the Congo because of its use of child soldiers, it took the Congolese government only five days to sign an action plan with the United Nations to end its use of children. Since then, the government has stopped recruiting children and demobilized many more.

When the administration used the law to persuade Chad to stop using child soldiers, Chad conducted age verification of thousands of its troops, criminalized child recruitment, and imposed penalties for recruiters who failed to comply. Last year, the UN received no new reports that Chad was recruiting children, and this year, it removed Chad from its list of violators.

The State Department identified nine problem countries this year, but the administration announced that only three would be barred from U.S. military assistance. For the other six, Obama used his presidential authority to give partial or complete waivers.  Yemen, for instance, may receive $25 million in U.S. military financing in the FY2015 budget, with no strings attached. Yemen signed a UN agreement in May to end its use of child soldiers, but is a long way from eliminating the problem. At least part of that money could be withheld until Yemen takes stronger action. The only excuse the US has offered is that Yemen has made “some progress” and that it is in the US “national interest” to provide the funding.

Another missed opportunity is Somalia, where the UN documented nearly 1,300 cases of child recruitment in 2013, including hundreds by the Somali National Army and its allied militias. Yet the administration gave Somalia a full waiver as well, allowing it to get  $115 million. A smarter choice would be to withhold some of that assistance until Somalia puts systematic screening procedures in place and gives the UN unimpeded access during all recruitment efforts and to formal and informal military installations to inspect for child soldiers.

In its Sept. 30 statement, the White House said that three of the countries using child soldiers – Burma, Syria, and Sudan – would not receive any U.S. military assistance, but that with three others—Congo, South Sudan, and the Central African Republic—the administration is withholding some assistance, while allowing other aid to flow. In Congo’s case, that choice was the right one: the government has made substantial headway, but a partial withholding will send a clear message that the U.S. expects greater progress.

But the decisions on the Central African Republic and South Sudan are troubling.  Both countries have had a dramatic escalation of fighting in the last year, with sharp spikes in child recruitment. In both countries, children have been thrown into battle on the front lines. UNICEF estimates that as many as 6,000 children have fought in the Central African Republic, and as many as 9,000 in South Sudan.

When the child soldier problem in both countries is only getting worse, partial waivers can send the wrong message. The partial waiver for South Sudan allows the U.S. to continue to support cease-fire monitors and efforts to counter the abusive Lord’s Resistance Army – laudable goals. But the waivers should have been accompanied with strong public statements that the use of child soldiers is unacceptable and that meaningful military support will remain cut off until concrete steps are taken  – including accountability for the unlawful use of children in armed conflict.

Just two weeks ago, the U.S. ambassador to the United Nations, Samantha Power, chaired a meeting of the UN Security Council on children and armed conflict. She said: “Perpetrators have to be held accountable. Groups that fail to change their behavior must be hit where it hurts.”

The administration’s actions should match its fine words.

Becker is the children’s rights advocacy director at Human Rights Watch.