With little fanfare, the Pentagon last week increased the American military presence in northeastern Syria—sending some 100 soldiers and six Bradley fighting vehicles. Jonathan Spyer explains why:

On August 26, four U.S. servicemen were wounded when the vehicle in which they were traveling collided with a Russian military vehicle. The incident took place . . . at the northeastern tip of Syria close to the Tigris River and the border with Iraq. This area lies far east of the Euphrates, and well inside of territory designated as a U.S.-controlled security zone. That is, the Russian presence in the area was itself a provocation. The collision with the U.S. vehicle took place at a time when Russian military helicopters were deployed above the area. It appears to have been deliberately initiated by the Russian force.

This incident reflects a broader pattern. Moscow [believes] that the American presence in eastern Syria lacks a clear strategic [rationale], and hence may be withdrawn if sufficient pressure is applied to it. Moscow wants to see Syria reunited under the rule of President Bashar al-Assad, as a weak and dependent client of Russia. The Kurdish-controlled, U.S.-guaranteed area east of the Euphrates, comprising around 25 percent of the area of Syria, currently stands as a barrier to the achievement of this goal.

The Russians therefore appear to be attempting to whittle away at the American presence, gradually expanding their own area of activities. . . . Parallel to the campaign of harassment, the Russians are seeking, slowly and incrementally, to draw the Kurdish ruling authorities in this area back under their political patronage. . . . The slow-moving contest over the ruins of Syria thus looks set to continue.

Israel will likely respond directly against Iran after yesterday’s attack, and has made known that it will calibrate its retaliation based not on the extent of the damage, but on the scale of the attack. The specifics are anyone’s guess, but Edward Luttwak has a suggestion, put forth in an article published just hours before the missile barrage: cut off Tehran’s ability to send money and arms to Shiite Arab militias.

In practice, most of this cash comes from a single source: oil. . . . In other words, the flow of dollars that sustains Israel’s enemies, and which has caused so much trouble to Western interests from the Syrian desert to the Red Sea, emanates almost entirely from the oil loaded onto tankers at the export terminal on Khark Island, a speck of land about 25 kilometers off Iran’s southern coast. Benjamin Netanyahu warned in his recent speech to the UN General Assembly that Israel’s “long arm” can reach them too. Indeed, Khark’s location in the Persian Gulf is relatively close. At 1,516 kilometers from Israel’s main airbase, it’s far closer than the Houthis’ main oil import terminal at Hodeida in Yemen—a place that was destroyed by Israeli jets in July, and attacked again [on Sunday].