The Police’s fourth album investigates an electronic sound while adopting their most explicitly political stance yet. “Spirits In the Material World”’s revolution-rock bobs to a reggae rhythm driven by keyboards rather than guitars, while “Invisible Sun” examines The Troubles in Northern Ireland against an eerie, electro swirl. They’ve not banished love songs though and with a chorus that bursts out of the synth mist like a thunderclap, “Everything Little Thing She Does Is Magic” is one of their finest.