In 2008, Johnstone represented the state of Montana in a case against Canyon Ferry Road Baptist Church. The church, located in
East Helena, Montana, believed that marriage may exist only between one man and one woman. The church challenged certain provisions of Montana's campaign finance law requiring reporting and disclosure of campaign contributions or expenditures.[7][8]
Federal judicial service
On September 2, 2022, President
Joe Biden announced his intent to nominate Johnstone to serve as a
United States circuit judge for the
Ninth Circuit.[4] On September 6, 2022, his nomination was sent to the Senate. President Biden nominated Johnstone to the seat to be vacated by Judge
Sidney R. Thomas, who announced his intent to assume
senior status upon confirmation of a successor.[9] Senator
Steve Daines of
Montana opposed his nomination, saying that Johnstone was too political and partisan to be a judge and that the White House had not adequately consulted him on the nomination.[10][11][12][13][14] On October 12, 2022, a hearing on his nomination was held before the
Senate Judiciary Committee.[15] He was questioned about his views on election integrity and religious freedom issues.[16] On December 1, 2022, his nomination was favorably reported by the committee by an 11–10 vote.[17] On January 3, 2023, his nomination was returned to the President under
Rule XXXI, Paragraph 6 of the
United States Senate; he was renominated later the same day.[18] On February 2, 2023, the committee failed to report his nomination by a 10–10 vote.[19] On February 9, 2023, his nomination was favorably reported by the committee by an 11–10 vote.[20] On April 25, 2023, Majority Leader
Chuck Schumer filed
cloture on his nomination.[21] On April 27, 2023, the Senate invoked cloture on his nomination by a 50–45 vote.[22] On May 1, 2023, his nomination was confirmed by a 49–45 vote.[23] He received his judicial commission on May 5, 2023.[24]