Former U.S. Senator David Durenberger, a Minnesota Republican who espoused a progressive brand of politics and criticized the GOP after his political career, died Tuesday at age 88. Durenberger’s health had declined in recent months, his longtime spokesperson Tom Horner said. Horner told The Associated Press that Durenberger died Tuesday morning of natural causes. He was at his St. Paul home surrounded by family. Durenberger — a former executive secretary to GOP Gov. Harold LeVander, former corporate attorney and former captain in the U.S. Army Reserve — won a U.S. Senate seat in 1978. He served three terms and championed health care reform. He pushed proposals to expand Medicare benefits, protect rights for disabled people, including the landmark Americans with Disabilities Act, and to promote gender equity. "Senator Dave Durenberger was a true public servant," Democratic U.S. Sen. Amy Klobuchar , of Minnesota, said in a statement. Klobuchar, who holds Durenberger’s old