On January 1, 1997, he was seconded by the Federal Government to be the Treaty Commissioner for the Province of Saskatchewan for a 10 year period.
Judge Arnot’s work on the "Teaching Treaties in the Classroom Project" was specifically cited as a model for Canada by the United Nations Special Rapporteur on Racism in his report presented in March 2004.
In October 2005, the Office of the Treaty Commission was selected by the Canadian Race Relations Foundation to receive its biennial Award of Excellence for education programs in the public and government sector.
Judge Arnot introduced the phrase "We are all Treaty people" to capture the nature of the Treaty relationship in Canada.
He has produced and directed a number of video education projects. He has been involved in education for the Judiciary through the National Judicial Institute, the Western Judicial Education Centre, the Canadian Association of Provincial Court Judges, and the American Judges Association.
He was honoured by the Canadian Bar Association Saskatchewan Branch as a recipient of the "Distinguished Service Award" for 2007.
He was seconded from the Provincial Court of Saskatchewan to be Chief Commissioner for the Saskatchewan Human Rights Commission on January 15, 2009 for a five year term. On January 15, 2014, Judge Arnot was reappointed as Chief Commissioner for an additional five year term.