The following is an excerpt from The Case for a More Robust Intervention in Syria by Century Foundation fellow Thanassis Cambanis.

American engagement in Syria should revolve around three imperatives: assist, protect, pressure.

1. Assist

On assistance, the United States is already the biggest single financial donor to Syrian aid. But it is more than just dollars that matter; total American aid to refugees and other victims of conflict—including support for resettlement, health care, and education—should equal that of major donors such as Turkey and Europe. America has been generous, but it should achieve more in effective help than any other state, in order to justify its role as honest broker. The United States should double its already generous humanitarian expenditures.

2. Protect

On protection, U.S. military force should quickly and decisively be brought to bear to protect vulnerable civilian populations and infrastructure. As a first step, protection requires using military force to prevent or retaliate for some of the most egregious and indiscriminate attacks on civilians. Protection actions would include shooting down some helicopters and planes, in order to reduce the amount of barrel bombs and conventional bombs dropped on civilian, rebel-held areas; retaliating against sources of fire on medical facilities, markets, schools, and civil defense facilities; and quick, decisive strikes against government forces or their allies who are besieging civilians or interfering with the flow of humanitarian aid.

3. Pressure

On pressure, America should push the Damascus government and its opponents to engage in serious negotiations, using military action and the White House’s bully pulpit. Serious talks require major concessions, which are more likely if the United States uses its considerable influence to make sure that all the potential spoilers (including Assad, Islamic State, and Nusra) know the United States will prevent them from achieving outright victory. The thrust of U.S. escalation is that it might produce, in the long run, a significant de-escalation of the entire Syrian conflict. And if it does not, the United States at least will be able to save and protect many civilian lives, and to reap strategic and political benefits throughout the region from having taken a more active role in Syria’s fate. It will also shift the burden of the war to be more equitably shared by the government and its forces, and not, as is currently the case, overwhelmingly by civilians in rebel-held area. A wise U.S. president need not be locked into further escalation; limited military intervention is only a slippery slope if the United States fails to exercise discipline.

Why a Three-Pronged Strategy Could Work

The military, political, and humanitarian investment should have the goal of pushing Syrians to reach a negotiated settlement to the civil war. Since the summer of 2015, the U.S. Department of State has been engaged in sustained high-level diplomacy surrounding the conflict, representing the one pillar of the policy where American engagement already is where it should be. Military and humanitarian pressure should rise to a level that is in balance with the political commitment to diplomacy. Military intervention (and humanitarian aid) should shore up non-jihadi rebels (up to and including Ahrar el Sham, if it continues its practical collaboration), and should punish the government when it is possible to do so without hurting civilians. In some cases the to-do list is clear: quick air strikes to support any vetted rebel group that is about to be overrun by the government, Nusra, or Islamic State; lethal force to protect any vulnerable population, such as internally displaced people in camps threatened by jihadists or by the government; and sustained military aid to end siege warfare and keep supply routes open.