A Shiite militia that refuses even to identify its leader is emerging as one of the greatest threats to the Iraqi administration it’s meant to be backing. Kataib Hezbollah has thousands of fighters deployed against the jihadists of Islamic State. While the Iranian-backed group has played a key role in helping Prime Minister Haidar al-Abadi stem the militants’ advance, it’s now joining forces with other Shiite militias to oppose the premier’s push to enact a measure that could limit its own power, and Tehran’s influence. At the heart of the dispute is the National Guard Law, legislation meant to bring all pro-government armed groups under a unified command. The measure is backed by the U.S. as the only way to halt the breakup of OPEC’s second-biggest oil producer. “We reject this law and we will chase anyone who votes for it in the Iraqi parliament,” Jaafar al-Husseini, a spokesman […]