At their peak, Gang of Four stylized 1970s dissent into cutting post-punk. Sadly, the qualities that once made the English act so influential are gone on its ninth LP, and first since co-founding singer Jon King’s departure. The question posed by the record’s title is not one the band seems to know how to answer. In place of once-sharp radical jabs, we get empty alarmism. “Obey the Ghost” is full of vague Illuminati archetypes: “We’re Facebook friends with celebrities,” new singer John “Gaoler” Sterry accuses over ominous video-game chirps. The only threat it brings to mind is that Frogger might not cross the street in time.