In 1934 he [William Langer, Governor of North Dakota -JG] was indicted for conspiring to interfere with the enforcement of federal law by illegally soliciting political contributions from federal employees, and suit was filed in the State Supreme Court to remove him from office. While that suit was pending, he called the State Legislature into special session. When it became clear that the court would order his ouster, he signed a Declaration of Independence, invoked martial law, and called out the National Guard. Nonetheless, when his own officers refused to recognize him as the legal head of state, he left office in July 1934. As with Adam Clayton Powell, however, the people of the State still wanted him. In 1937 they re-elected him Governor and, in 1940, they sent him to the United States Senate.
The quotation is from Justice Douglas's concurring opinion in Powell v. McCormack. The House of Representatives, on misappropriation of funds grounds, had refused to seat Powell, although it was undisputed that he was the legitimate winner of his district's 1966 election to the 90th Congress.
Powell sued, although the Supreme Court didn't hear his case until 1969. In the meantime, Powell had won the 1968 Congressional election and taken his seat in the 91st Congress. Langer shows up in the Powell opinion because the Senate debated for over a year whether to seat him, ultimately deciding that it lacked the power to exclude him.