President Obama’s decision to provide the Syrian opposition with $60 million in aid – while continuing to withhold weapons – will disappoint those who have argued that the United States should step up its role in the battle to overthrow President Bashar Assad. But the administration is right: Arming the rebels now would be a mistake.

On Thursday, Secretary of State John F. Kerry announced the new aid program, which he said would help the Syrian opposition coalition deliver food, medicine, sanitation and education. Also, for the first time, food and medicine would be provided directly to units of the Free Syrian Army. Kerry suggested, the aid package could help to “change President Assad’s calculation” and, in concert with economic sanctions and renewed diplomatic pressure, induce him to step down.

Advocates of arming the rebels believe that more must be done to pressure Assad, who remains in power after nearly two years of fighting and an estimated 70,000 deaths.

But the arguments on the other side are stronger. There is no guarantee that arming the Free Syrian Army would significantly hasten Assad’s overthrow, and there remains the possibility that weapons provided to trusted groups would find their way to the radical Islamist fighters who constitute a second front in the opposition to Assad. Some advocates of arming the rebels, such as Sen. John McCain, R-Ariz., also favor the establishment of a no-fly zone over Syria comparable to the one NATO imposed in Libya – an operation that began with seemingly limited aims but rapidly mutated into a major campaign of aerial bombardment.For now, the administration is right to withhold arms from the rebels, even as it seeks to pressure Assad in other ways and to shape the future of the Syria that will exist after the dictator is driven from power. For the Syrian people, that can’t be too soon.