Russia has retaliated by threatening to treat American planes as targets; in a dramatic “Top Gun”-style maneuver on Monday, one of Moscow’s jets buzzed within five feet of an American spy plane.
None of these encounters involved the Islamic State. The contradiction opens a larger question, national security experts say, of what kind of broader strategy the Trump administration plans once the Islamic State — now on the defensive — is defeated in Syria.
With each episode, “we own more of the conflict in Syria without articulating a strategy,” said Vali Nasr, dean of the Johns Hopkins School of Advanced International Studies. “We are sleepwalking into a much broader military mandate, without saying what we plan to do afterward.”
American military gains in Syria have far outpaced any diplomacy toward a political settlement of the Syrian civil war.
When President Barack Obama first began airstrikes against Islamic State targets in Syria three years ago, the instructions to the Pentagon seemed clear: Defeat the Islamic State through alliances with Syrians who oppose the brutal extremist group, but do not help them fight President Bashar al-Assad.
The Islamic State is now reeling in Syria. It has been battered by strikes from a host of enemies, from the United States and its regional allies to the Syrian government that is backed by Russia and Iran. It no longer holds one-third of the country, according to American officials who say that the group has lost around half of the territory it once controlled.
In past years, the Pentagon and its allies could stay out of the Syrian government’s way — and that of Mr. Assad’s backers in Russia and Iran — as all fought the Islamic State. Now, all sides are converging on a smaller piece of territory, resulting in competing forces increasingly turning on one another, in addition to the common enemy.
Captain Davis, at the Pentagon, noted that when American-backed…