This article was first published on Foreign Policy.

In June 1967, Egypt closed the Straits of Tiran to Israeli vessels, blockading Israel's access to Asia and Africa. Knowing that this meant imminent war, the Lyndon Johnson administration asked Congress to support a multinational flotilla to break the blockade. But Congress wasn't buying. Secretary of State Dean Rusk explained congressional reluctance with one word: "Tonkinitis." Having been lured into a raging land war in Asia because of one maritime confrontation, Congress was not going to be lured into a Middle East war because of another, especially one not of their making.

It could be argued that an analogous condition is evident in current U.S. policy deliberations. But to be clear, if the United States is suffering from a latter day Tonkinitis, driven by America's unsuccessful venture in Iraq, that is not a bad thing.  At this stage, the Obama administration is wise to resist calls for engaging more directly and intensively in Syria's civil war or Iraq.

The use of the comparative on Syria here is essential, because the United States already is engaged in the Syrian conflict. Washington took the Syrian opposition's side immediately, mobilized international support in the form of the Friends of Syria, imposed the harshest possible economic sanctions on the Bashar al-Assad regime, supplied non-lethal assistance and funding for the political opposition beginning in 2011, reportedly facilitated large shipments of weapons on behalf of Saudi Arabia in 2012, began to supply arms covertly in 2013, according to published reports, to the armed wing of the rebellion, and emerged early on as the world's largest source of humanitarian aid by a very wide margin. There should be no question about whose side the United States is on, or whether Washington should get involved. It already is.

Although Washington's preferences regarding Syria are clear, it is at least an open question whether it is even possible to secure those preferences. This would a thorny issue no matter what, but in this instance the deliberative process is burdened by an anterior problem: The inability of proponents of more muscular intervention to explain how American strategic interests in Syria would justify the costs and risks of escalation. These voices have become increasingly -- and rightly -- anguished as the toll in Syrian lives has risen. Yet, what they really have been arguing for is America's "responsibility to protect" vulnerable noncombatants against violent assault. The outrage is real. It is thought that 200,000 people have perished. With 6.5 million people displaced within Syria and nearly 3 million refugees in neighboring countries, the scale of the disaster is nearly incomprehensible. As the horror has unfolded, U.S. humanitarian assistance has grown. Thus far, U.S. spending -- about $1.7 billion -- dwarfs donations by the EU, Russia, China, and the Gulf states. And that number will certainly increase further in the coming years.

There is a vital need to articulate the link between means -- the direct and indirect costs of intervention and our available resources -- and ends -- our strategic stake in Syria. It has been the instinct of successive administrations -- at least since the Balkan wars of the 1990s -- to require clear strategic interests and objectives for military intervention, or actions that could put the nation on a path to it. (The George W. Bush administration was, concededly, a large exception.) Thus, proponents of intervention in Syria have cast their arguments in terms of four overlapping Considerations: spillover; reputation; rollback of Iran; and the jihadist challenge. These factors, they argue, make intervention imperative.

Continue reading this article at Foreign Policy.