Frank Steunenberg came to Idaho from Iowa in 1886, settling in Caldwell, where he was involved in publishing a newspaper with his brother. He served as a delegate to the state constitutional convention in 1889 and was a member of the Idaho House of Representatives in the first state legislature from 1890 to 1893. In 1896, he was elected Idaho's fourth governor, was re-elected in 1898 for another two-year term. He was a Democrat, who gained the top office in state government with Silver Republican, Populist, and labor support.
In 1899, striking miners in the Coeur d'Alene mining district of north Idaho blew up the Bunker Hill and Sullivan Mine concentrator, and there was virtual armed warfare in the mining community. Governor Steunenberg declared martial law. Because the Idaho National Guard was in the Philippines, because of the Spanish-American War, Steunenberg called on President McKinley to send in federal troops to reestablish law and order.
The federal troops arrested a large number of the striking miners and herded them into "bull pens," which were lacking in proper sanitation, poorly equipped, and caused the miners to become very agitated. The Western Federation of Miners, a union that represented the striking miners, blamed Steunenberg directly for this humiliation and for the harm to their members.
On the evening of December 30, 1905, Steunenberg was assassinated by a bomb placed at the gate to his residence in Caldwell.