Last week, close watchers of the many-sided war in Iraq and Syria learned from an apparently inadvertent Russian state television disclosure that Russia has upped the ante in its eight-week-old war in Syria, apparently adding ground-based artillery to the array of attack jets, strategic bombers, and helicopter gunships that have been pounding Islamic State terrorists and U.S.-backed rebels alike in the country.

Without fanfare, the U.S.-led coalition has escalated its involvement in the conflict in a similar way in recent weeks, adding artillery raids of its own to the steady thrum of air strikes against the Islamic State. In the U.S. case, the weapons involved are long-range, satellite-guided rockets, not howitzers, and the targets are in Iraq, not Syria.

Operation Inherent Resolve spokesman Col. Steve Warren first acknowledged the use of the M142 High Mobility Artillery Rocket System, or HIMARS—a staple of U.S. operations in Afghanistan—during a briefing last month. Since then, Inherent Resolve press releases have noted the use of rocket artillery on eight more days, most recently Sunday, when “rocket artillery” accounted for an unspecified number of 19 coalition strikes in Iraq. […]