Five months into the conflict, the U.S. and Iran are running up against the limits of what military force can achieve. As President Trump threatens to ratchet up the bombing campaign and Tehran's militia allies widen the war, both governments have shown a willingness to escalate. Jared Malsin explains why the war risks becoming a prolonged test of endurance rather than a decisive showdown.

Also worth your time is our profile of Troy Jackson, the former Maine Senate president expected to become the Democratic nominee against Sen. Susan Collins. He inherits a race transformed by Graham Platner's abrupt exit—and must convince voters he can harness the oysterman's populist appeal without carrying his baggage.