The U.S. Chamber of Commerce announced Tuesday that it was backing the businessman and former state lawmaker, who is challenging Sen. Joe Donnelly.

U.S. Sen. Joe Donnelly (D-Ind.) and Republican challenger Mike Braun both seek to assure seniors they'll protect Medicare and Social Security.

With less than two months until the election, Mike Braun has yet to purchase air time for October, while incumbent Joe Donnelly (D-Ind.) has outspent him by almost double on TV and radio since June, records show.

Indiana Democratic Sen. Joe Donnelly talks with Here & Now's Jeremy Hobson about his Senate race against former state Rep. Mike Braun.

The Senate Leadership Fund on Tuesday announced the campaign, which will run across the state on broadcast TV, cable, radio and online.

It's been several election cycles since the Indiana FOP endorsed a candidate in a U.S. Senate race.

President Trump spoke about trade, immigration and coal during the rally in Evansville. He also supported Republican Mike Braun in his bid to unseat U.S. Sen. Joe Donnelly (D-Ind.).

The rally has already filled up the convention center's hotel and forced the cancellation of a Red Hot Chili Peppers concert.

The campaign says Trump will talk about economic policies and stress his support for the GOP Senate candidate Mike Braun.

The complaint alleges Republican Senate candidate Mike Braun didn't properly file information about a loan he made to his campaign.