The first thing you see in the room is Donald Trump. Thumbs up, white teeth locked in a grin. He has been here for months. 

“We love Trump!” gushes Betty DeHaven, looking up at the six-foot cardboard cutout of America’s 45th president. “I like that he is open. He says what he likes.”

At the Republican Party’s headquarters in Martinsburg, a quaint town of some 20,000 people in West Virginia, it seems Betsy, a 73-year-old volunteer, is not alone. 

Posters and leaflets for those running in Tuesday’s midterm elections boast of endorsements from the president. Some simply carry the word TRUMP in lettering as large as the candidate’s own names. Everything is done to play up a link to the commander-in-chief. …