The Washington Post reports: For weeks, U.S.-backed forces have been fighting to oust the Islamic State from key areas of northern Iraq in a series of small-scale battles that could have an enormous impact on the group’s “caliphate.”

A major prize in the clashes is a highway that serves as a lifeline for the Islamic State. It runs from the group’s Iraq stronghold in Mosul to its enclaves in northeastern Syria, including its self-styled capital, Raqqa, 300 miles away.

The battles are occurring as Islamic State is causing growing alarm internationally over its brutal actions, which have included the murder of a captured Jordanian pilot and the beheading of 21 Egyptian Christians by Libya-based adherents of the extremist group.

In late January, however, Islamic State fighters suffered a setback as Iraqi Kurdish forces seized a stretch of the key highway at the town of Kiske, west of Mosul.

The Islamic State is still using the highway, detouring onto back roads to get around Kiske. But if the Iraqi Kurdish fighters can maintain and expand their hold on the road, the Islamist extremists “will be under a kind of siege in the area. It will be very hard for them” logistically, said Hisham al-Hashemi, an Iraqi researcher who is an expert on the radical group. [Continue reading…]