"I am not a scientist," Senate Republican Leader Mitch McConnell has said numerous times, a response that other members of his party have parroted.
Republicans are running strong races against endangered Democratic incumbents in states such as North Carolina, Colorado, Arkansas, Louisiana and Alaska. Republicans are also looking to replace retiring Democrats in Iowa and West Virginia with a GOP lawmaker.
Nationally, Republicans must gain six seats to win Senate control. The most competitive races, many in states where Obama lost in 2012, remain too close to call.
Republican congressman Vance McAllister is trying to make up to Louisiana voters for getting too close to a married former employee.
The Baton Rouge Republican has repeatedly battled a perception within his own party that he perhaps wasn't the best choice to carry the GOP banner.