With little notice and no fanfare, although the New York Times mentioned it the other day, the Gulf Arab states have withdrawn from significant participation in the war in Syria. This move involves in particular the air forces of Saudi Arabia and the United Arab Emirates. These are some of the same Arab governments that screamed long and loud about the need to do more in Syria. They are so exercised over the conflict in Syria that they are willing to fight there to the last American.

The Saudis and their colleagues are shifting most of their own air power to their armed intervention in Yemen. That intervention does nothing to advance U.S. interests, even though Washington managed to get itself maneuvered into supporting that expedition, too, through means short of direct U.S. military involvement. The Saudi-led air assault on Yemen has greatly exacerbated a humanitarian tragedy there. The side on which the Saudi have intervened—a side that includes Al Qaeda in the Arabian Peninsula (AQAP)—is not one that the United States has any good reason to be identified with. Even if the United States had a good reason to take sides in the Saudis' contest with Iran for regional influence, which it doesn't, the Yemeni war would be a poor place to do so; the Houthi rebels, who are the staunchest Yemeni foes of AQAP, are not proxies of Iran and do not do Tehran's bidding.

Back in Syria, it's not as if the departure of the Gulf Arab forces makes much of a dent in what the United States is trying to do militarily. There has always been a big disconnect in the priorities and objectives that each government has had there. The Saudis have seemed even less interested in countering ISIS, as distinct from being fixated on the fate of the Assad regime, than the Russians have been, although they and the Russians are, of course, on opposite sides regarding the status of that regime. But more important than the direct material impact is the symbolism of whether the United States does or does not have broad support and joint participation for what it is doing in Syria. The withdrawal of Arab air forces makes the U.S. role all the more lonely and conspicuous. Participation of other Western powers already was lukewarm, and the U.S. role will get lonelier still with the promise by the new Trudeau government in Ottawa to end Canadian participation in military operations in Syria. All of this makes the United States that much more of a salient target for anger over the no-good-solution Syria situation and for related reprisals, including those of the terrorist variety.

The Syrian case and especially adoption of the “Assad must go” standard is one of the latest examples of how the United States, through several presidential administrations, has repeatedly allowed itself to get sucked into other people's quarrels in the Middle East. These include quarrels in which the United States should not have gotten involved at all, or in which it had no good reason to take the side it was enticed to take. Generous quantities of moral hazard often have been involved in that the United States has assumed burdens that were defined or created by someone else. The usual nature of political debate and the political process within the United States has exacerbated the problem. The tendencies to discuss any overseas problem as if it necessarily has a U.S. solution, and to invoke the need to support “allies” even when there is no treaty commitment and regardless of the nature of the particular issue at hand, put pressure on the administration of the day to take sides and to assume burdens. The burdens that have been assumed despite being contrary to U.S. interests have included ones defined by Gulf Arabs and certainly ones created by Israel.

The United States does have a interest, from the standpoint of counterterrorism, mitigation of refugee flows, and regional stability, to be deeply involved in multilateral diplomacy aimed at de-escalating and eventually resolving the extremely complicated conflict in Syria. While engaging in that diplomacy, and in crafting reactions to the ideas and proposals of others, including from Russia, U.S. policy-makers need to be careful not to slide into the habit of adopting the objectives of others just because they may be commonly labeled as “allies.”