Josh Rogin and Eli Lake write: Syrian Kurds are now attacking U.S.-supported rebels, but U.S. officials disagree about whether the Kurds have switched sides — and about whether the U.S. should continue increasing its arms support for them, as opposed to focusing support on Sunni Arab rebels.

Kurdish fighters have taken advantage of the Russian-backed Syrian regime offensives in the north of the country, seizing territory from U.S.-backed rebels who are on the defensive. But factions within the Obama administration disagree about whether the Kurds are simply being opportunistic, or have coordinated their attacks with Russia, Iran and the Syrian regime.

Some administration officials told us that U.S. intelligence has documented meetings between the Kurds’ armed group and officials in the Iranian Revolutionary Guards Quds Force, which has fought alongside the Assad regime against the opposition since 2011. This faction also says the Kurdish group, the YPG, is closely working with the PKK, a Kurdish terrorist organization at war with Turkey. [Continue reading…]