Russian and US warplanes are each backing rival sides as the Assad regime and Kurdish-led Syrian Democratic Forces (SDF) race to take the ISIS de facto capital of Raqqa. The Kurdish-led forces are in the lead. SDF fighters this week entered the ISIS-held city of Manbij, a key step toward Raqqa. (Al Jazeera, June 23) ISIS is meanwhile reported to have taken back large areas of territory in Raqqa governorate that had recently been taken by regime forces. (Al Jazeera, June 21) The Russian air-strikes in support of the regime forces, as ever, are more indiscriminate. Local monitoring group Raqqa is Being Slaughtered Silently (which operates "underground" in ISIS-controlled territory) reports that 32 civilians were killed and 150 injured in Russian strikes on Raqqa city. (Al Jazeera, June 22)

Russia's campaign of aerial terror remains even more intense elsewhere in Syria—where it is targeting Syrian opposition forces hostile to ISIS. Russia is breaching international conventions by dropping "incendiaries similar to white phosphorus" on residential areas of Aleppo in an apparent prelude to a ground offensive to retake the city from rebel forces. Citing sources on the ground, the London Times also reports that "what experts believe to be a thermobaric bomb, the most powerful explosive apart from a nuclear weapon," was used in Aleppo. (NATO forces have used thermobaric bombs in Afghanistan, but this would mark the first time this weapon has been used in Syria.)

The LA Times ominously reported June 17 that "Russian warplanes hit Pentagon-backed Syrian fighters with a barrage of airstrikes earlier this week, disregarding several warnings from US commanders in what American military officials called the most provocative act since Moscow's air campaign in Syria began last year." The account is light on specifics, telling us only that the strikes "hit a base near the Jordanian border, far from areas where the Russians were previously active, and targeted US-backed forces battling the Islamic State militants."

This is particularly worrying when we recall that the US has a contingent of special forces embedded with the SDF in its drive on Raqqa. Russian air-strikes on actual US forces (with obvious implications for superpower confrontation, whether intentional or not) is clearly entering the realm of possibility.

This is a sobering factor in considering the letter issued by more than 50 diplomats through a State Department "dissent channel" calling on the US to take military action against the Assad regime: more specifically, "a judicious use of stand-off and air weapons, which would undergird and drive a more focused and hard-nosed US-led diplomatic process." (Sky News, June 17; NYT, June 16) (Lip service and popular perceptions aside, the US has thus far been tilting to Assad in the Syrian war.)

Moscow itself has sought to woo the Kurds as proxies, which may provide a brake on the possibility of Russian air-strikes on the SDF. But the apparent race for Raqqa may indicate that a line has been drawn between the Kurds and the regime (and therefore Moscow) over the Kurdish declaration of autonomy in Rojava, as they call northern Syria.

In another sign of Great Power repositioning, Reuters on June 17 offered this unlikely headline: "Turkey may soften stance on Assad exit as Kurdish gains force shift."  Days after taking office last month, new Prime Minister Binali Yildirim said Turkey needes to "increase its friends and decrease its enemies." An unnamed official from the ruling AK Party is quoted saying less obliquely: "Assad is, at the end of the day, a killer. He is torturing his own people. We're not going to change our stance on that. But he does not support Kurdish autonomy. We may not like each other, but on that we're backing the same policy."

Once again, that's why they call it a Great Game.