Updated: 8:14 p.m.

Former Republican Sen. Malcolm Wallop died at his home in northern Wyoming on Wednesday, Sen. Mike Enzi (R-Wyo.) announced on the Senate floor.

Wallop was 78.

“He’s been ill for some time, but he has had a very active life and made a great deal of difference in this body,” Enzi said. “For all of his three terms, he was a powerful and effective presence in the Congress that ensured people of Wyoming that they were heard, and that their concerns were being addressed.”

Wallop represented Wyoming in the Senate from 1977 to 1995, and he spent that time aggressively pursuing energy and environmental policy on behalf of the constituents in his home state.

Wyoming is rich with oil, natural gas, coal and uranium, and in 1992 Wallop became the ranking member of the Energy and Natural Resources Committee. There, he partnered with Chairman J. Bennett Johnston (D-La.) to push through a comprehensive energy plan that offered incentives for conservation, opened electric utility markets, and provided tax relief for oil and gas drillers.

“It is nothing short of miraculous, the number of interests that have come together in this,” Wallop said at the time.

He also helped create a fund to finance state fisheries and boating programs.

Although he was a third-generation Wyoming resident, wore cowboy outfits and rode horses in his campaign ads, Wallop had to fight to overcome his image as an East Coast elitist. He was born in New York City, was educated at Yale and had a grandfather who once sat in the British House of Lords.

Wallop was a rancher and meatpacking executive before his career in public service. He also served two terms in the Wyoming House and one term in the state Senate.

Wallop is survived by his wife, Isabel, and four children.

Niels Lesniewski contributed to this report.