Independent Dan Osborn announced another bid to represent Nebraska in the Senate on Tuesday, challenging GOP Sen. Pete Ricketts after his loss in an unexpectedly competitive race against a Republican incumbent last year.

Former labor union leader and independent candidate Dan Osborn has announced his bid for a Nebraska U.S. Senate seat, challenging Republican Sen. Pete Ricketts.

Independent populist Dan Osborn, whose insurgent Senate campaign seriously threatened one of Nebraska’s Republicans from securing a third term last year, is now taking on GOP Sen. Pete Ricketts — one of the wealthiest members of Congress.