Former Montana Sen. Conrad Burns, a former cattle auctioneer whose folksy demeanor and political acumen earned him three terms and the bitter disdain of his opponents, died Thursday. He was 81.

Burns died of natural causes at his home in Billings, Montana Republican Party Executive Director Jeff Essmann said.

“He was a colorful figure who loved people, politics and to serve,” Essmann said. “He brought a common-man, common-sense approach to his work in the Senate and returned to his home in Billings when his work was done.”

As a Republican senator, Burns used his influence on the powerful Appropriations committee to set the course on energy development and public lands management across the rural West. But he was ousted from office in 2006 under the specter of scandal after developing close ties to “super-lobbyist” Jack Abramoff, who was later jailed for conspiracy and fraud.

No charges were ever filed against Burns, who dismissed criticism over the affairs as “old political hooey.”

After working as a livestock auctioneer, Burns in 1975 moved into broadcast radio, founding four stations known as the Northern Ag Network. The network eventually grew to serve 31 radio and TV stations across Montana and Wyoming, offering agricultural news to rural areas.

He sold the network in 1985 and — capitalizing on his name recognition — made his first foray into politics a year later, when he was elected commissioner for Yellowstone County in south-central Montana.

Before his first term was completed, Burns took on incumbent U.S. Sen. John Melcher, a two-term Democrat described by Burns opponent as “a liberal who is soft on drugs, soft on defense and very high on social programs.”

At the age of 53, he won election to the Senate by a 3-percentage-point margin. He rose to be one of the most influential positions in Washington with his seat on the Appropriations committee, serving as chairman of the Interior subcommittee.

Burns became a strong advocate for increased domestic energy production and expanded development of natural resources. But even before his first term was over, Burns’ loose-talking ways — once credited with earning him favor among Montana’s rural electorate — landed him in trouble.

After the passage of the Civil Rights Act of 1991, the senator invited a group of lobbyists to a “slave auction” and later used a racial slur for blacks when relating a conversation he had with a Montana rancher. The resulting furor had little impact on his 1994 campaign, which he won in a landslide.

During the 2000 campaign, the controversy around Montana’s backslapping senator nearly caught up with him. He prevailed by only a thin margin over rancher Brian Schweitzer, who went on to become governor four years later.

By the end of his third term, however, Burns had been affixed with the same Washington-insider label that he had used successfully against Melcher. His close ties to lobbyist Abramoff lent credence to the accusation, and his bid for a fourth term came up about 3,000 votes short against the president of the Montana Senate, Democrat Jon Tester.

Burns had long cultivated a reputation as being a plain talker, but by the time he left office, his incautious remarks had become legendary. The press catalogued derogatory comments directed at women, Arabs and even out-of-state firefighters who had come to Montana to battle a 2006 blaze near his hometown of Billings.

“He had that fresh approach of just saying what he thought and not being very political,” said Taylor Brown, a friend and fellow Republican who bought the Northern Ag Network from him. “That was probably his biggest weakness in the end. He just said what he thought.”

After leaving office, Burns went to work for his former chief of staff in a Washington lobbying firm, Gage Business Consulting. But the Abramoff scandal followed him, and he eventually gave away $150,000 in contributions from the lobbyist, his clients and friends.

After the U.S. Justice Department launched a probe of Burns’ ties to the affair, he said he made nearly 10 years of records from his Senate office available to the government for review, including all electronic records. When the investigation was dropped in 2008 with no charges filed, he said he had never been interviewed as part of the investigation.

He credited his “thick hide and clear conscience” for helping him withstand the public scrutiny.

“There’s a hundred lobbyists who walk through that door every week,” Burns said in 2006. “If you don’t have a deep-seated philosophy then you might find yourself getting lost. I vote my philosophy first.”

Burns suffered a stroke in 2009, leaving him hospitalized for three months. It weakened his body, but not his mind, and less than two years later he was blasting President Barack Obama for wanting “the whole country to become like an Indian reservation” at a rally of tea party supporters.

Born in 1935 in Davies County, Missouri, Burns studied agriculture at the University of Missouri for two years before joining the U.S. Marine Corps in 1955. He first came to Montana as a regional salesman for Polled Hereford World magazine, and later settled in Billings to become the manager of a regional livestock expo in 1968.