One American studies expert said that the Oklahoma Republican's past interaction with the Texas Democrat was "indicative of an explosive temper." Sen. Markwayne Mullin (R-Okla.) faced intense scrutiny from his fellow lawmakers during his Senate confirmation hearing this week over his past behavior — including an accusation from Sen. Rand Paul (R-Ky.) that he has “anger issues.” But he also had a moment with Rep. Al Green (D-Texas) last month that revealed quite a lot about him, according to one