CRESCO, Iowa — When the surge of conservative populism started sweeping the Republican Party in the fall of 2015, Howard County Republican Party Chairman Neil Shaffer remained firmly behind Sen. Marco Rubio (R-FL) when he went to caucus in January 2016.

Shaffer eventually warmed to Donald Trump and went on to vote for him in November of that year. It was a vote that made him part of a coalition that turned Howard County, which lies here in northern Iowa on the border with Minnesota and not that far from the Wisconsin state line, Republican for the first time since Ronald Reagan in a presidential election.