WASHINGTON (AP) — The two billionaire mega donors poured $1.25 million into a super PAC that was supposed to supercharge Chris McDaniel's insurgent bid to be Mississippi's next Republican senator.

A year later, much of the money from Illinois shipping supply CEO Richard Uihlein and New York financier Robert Mercer is gone. Only a fraction was spent reaching voters who could boost the former state lawmaker's uphill battle against Cindy Hyde-Smith, Majority Leader Mitch McConnell's preferred candidate in a November special election that will determine who finishes out retired GOP Sen. Thad Cochr...