Last week, I came across Senate Majority Leader John Thune in a quiet marble stairwell, talking animatedly on the phone—a rare sight considering the quick-moving Republican leader doesn’t often conduct business in public. “If it’s not going to us, it’s going to China or Russia,” he said, sounding like he was trying to match the energy on the other end of the line. It was the morning of the Senate’s war powers vote on Venezuela, which Trump was watching closely, and Thune would soon be getting a much less cordial phone call. After five Republican senators voted to advance the resolution limiting the president’s use of force in Venezuela, Thune had a furious president on the line.