Barton was one of only eight justices of the High Court to have served in the Parliament of Australia prior to his appointment to the Court; the others were Richard O'Connor, Isaac Isaacs, H. B. Higgins, Edward McTiernan, John Latham, Garfield Barwick, and Lionel Murphy.
After 1906, Barton increasingly clashed with Isaac Isaacs and H. B. Higgins, the two advanced liberals appointed to the court by Deakin.