I think the disgrace that was the Kavanaugh hearings made many people take notice.
“…Nearly two thirds of registered voters showed a high level of interest in the election—the highest ever recorded in a midterm election since the Journal/NBC poll began asking the question in 2006.
“It’s a barnburner,” Bill McInturff, a GOP pollster who conducted the survey with Democrat Fred Yang, said of the surge of voter interest. “There’s a switch that’s been flipped…They are engaging in the campaign and the process.”…”
https://www.wsj.com/articles/interest-in-midterms-surges-boosting-trump-approval-rating-