I am sorry to say that I never seem to have heard of James Abourezk. At least not to the point that I remember him now.
He was elected, at age 41, to the Senate, on the very same day George McGovern famously lost his home state to Richard Nixon. This was November of 1972. He chose to step down, in 1978. So he served from 1973 to 1979. McGovern served until 1981, after he got clobbered in Nov 1980, while attempting to get another term. McGovern's replacement was the 3rd Arab American elected Senator, James Abdnor. Abourezk was the first. (The 2 were close childhood friends, but one was a liberal Democrat, while another was a Republican). (Adbnor lost his own reelection, in 1986, to Tom Daschle) (Daschle lost to John Thune, in 2004. Trump wants Republicans Thune defeated in 2022)
Abourezk is still alive, but his legacy involves the founding of the Arab American Anti Discrimination Committee , which is private, and started after his Senate career.
As a Senator, he was highly critical of the CIA and American foreign policy.
He pushed for a national referendum, known as the Nation Initiative.
Created the landmark Indian Child Welfare Act.
Created the Indian Self Determination Act, another landmark.
Instrumental in the creation of the American Indian Policy Review Commission and Select Committee on Indian Affairs.
Abourezk said he was and is a liberal, and he said he won his upset elections by working hard to communicate his controversial stances to voters who would not be expected to support such a candidacy. He ran for the House in 1970, but lost. He won the Senate election in a very Republican state, in a very Republican year: 1972.
It seems that a sincere progressive can win statewide in the most unlikely of places. Without hiding strongly held beliefs.
(Granted, this was before abortion and gun control exploded onto the political scene. His election came in a different time, for dure)