" Joe Biden, the occasionally foul-mouthed, frequently hot-headed caller of malarkey and all around loose cannon to Barack Obama's sophisticated good cop, is a career politician who has spent much of his time looking like the guy you can’t believe has made a career in politics. ... But I think he’s got a much better job lined up next."
good cop, bad cop
informal Used to refer to a police interrogation technique in which one officer feigns a sympathetic or protective attitude while another adopts an aggressive approach:questioners often play good cop, bad copfigurativethe prime minister and chancellor were involved in a classic good cop, bad cop routine