Unusual for a member of Congress, the 40-year-old Wisconsin Rep. Mike Gallagher is retiring later this year after only four terms in the House of Representatives. In a wide-ranging interview, Gallagher discusses what brought him to Capitol Hill and why he’s decided to depart so relatively soon; life inside a fractious Republican caucus; his legacy as chair of a House select committee examining the threat of an ambitious Chinese Communist Party; plus lessons learned from political and military service (Gallagher is an ex-Marine who served alongside Hoover senior fellow and Army Lt. Gen. H.R. McMaster in Iraq).