Bloomberg’s donation to the Super PAC supporting Cochran could end up becoming a kiss of death for Cochran in the heated runoff against conservative state Sen. Chris McDaniel, who bested Cochran in the popular vote in the primary a little over a week ago, forcing a runoff a week from Tuesday.

Bloomberg supports gun control—something Cochran says he’s against.

“This is not a battle of dollars, this is a battle for the hearts and minds of America so that we can protect our children, protect innocent people,” Bloomberg said in a recent television interview about his renewed fight against the National Rifle Association.