One after one, constituents took to the microphone to grill the first term Republican senator about the president — his attacks on John McCain, his emergency declaration at the border and why, in the opinion of several voters, Ernst hasn’t stood up to him more often.

“Other senators are speaking up criticizing Trump and defending McCain, but I have yet to hear one word from you,” one man implored her. “Is there no line Trump can cross that would cause you to break ranks with him?”…

Ernst better get used to it. At the same time she’s gearing for reelection, Democratic presidential candidates will be camped out in Iowa hammering Trump at every turn. The heightened attention on the president will test the political agility of Ernst, who has generally earned high marks in the state but is having to answer for Trump — whose poll numbers lag behind hers — and some of his unpopular policies.