FARGO, N.D. (AP) — Former North Dakota U.S Senator and Congressman Mark Andrews died at the age 94.

The Republican was virtually unbeatable after being appointed to the U.S. House in 1963. He served eight more terms as a congressman and a term in the U.S. Senate before an upset defeat in 1986.

Andrews surprised some Republicans with his criticism of some of President Ronald Reagan’s economic policies, once saying that “people in North Dakota didn’t elect me to be a rubber stamp.”