Dubois, who had a ranch near Blackfoot, began his political career by getting appointed U.S. Marshal for Idaho Territory in 1882. From that position, he successfully campaigned to disenfranchise Mormons from voting on the grounds that their practice of polygamy was against the law.
Next, Dubois ran as a Republican for the position of Congressional delegate from the territory, defeating the Democratic incumbent, John Hailey. He was in that position until 1890, when Idaho became a state. In those days U.S. Senators were elected by state legislators, and in Idaho Fred T. Dubois was elected as a Republican in 1891.
Dubois helped negotiate a treaty with the Nez Perce during his term in office, taking the opportunity to disparage the Bannock Tribe by calling them lazy and shiftless. Dubois served until 1896, when he was defeated.
In 1900, Dubois again ran for U.S. Senate, defeating his former ally George Shoup. It was a Democratic legislature that elected him, and he showed his thanks by becoming a Democrat a few months later. He is the only Idahoan who has served in the Senate as both a Democrat and a Republican.
Dubois had an anti-Mormon, anti-Indian reputation, and he added to that by showing his stripes as anti-Filipino, anti-black, anti-Japanese, anti-Chinese, etc. during his second term in the Senate.
The Idaho Legislature chose William Borah to replace Dubois in 1907. He would serve in the senate for 32 years.
Dubois died in 1930 and is buried in the Grove City Cemetery in Blackfoot (photo). Controversial as he was, Fred T. Dubois has two towns named after him, Dubois, Idaho and Dubois, Wyoming. The latter Dubois was given the moniker by the U.S. Postal Service, to the chagrin of residents who had another name in mind.