In the 1630s, the phrase 'judge advocate’, or variants thereof, became increasingly in common use. In 1639, for instance, an Advocate served with the Army of Charles I. On June 7, 1645, an Ordinance for constituting Commissioners and a Council of War for trial of all persons . . . appointed a Judge Advocate and a Provost Marshall. The Ordinance enabled and authorized the Judge Advocate to receive all “... accusations, articles, complaints and charges against all or any of the offenders...” By 1659, the Office of the JAG was created to supervise ‘courts martial’.
Prior to 1893, in the U.K. the JAG was a Privy Councillor, a junior Minister in the government, usually a Member of Parliament and a spokesman for the Commander in Chief in Parliament. In those days, the appointment was regarded as a political office and the JAG had direct access to the Sovereign on matters pertaining to their office. However, in 1893 the Judge-Advocate ceased to be a Minister. From that date the Office of the JAG was responsible for both judicial and advisory functions. That changed in 1948 when the UK Parliament decided to appoint a civilian member of the bench as the JAG and entrusted them with the exclusive role of chief magistrate of the penal military justice system accountable not to the military chain of command but to the Lord Chancellor.
Meanwhile in 1911, Canada appointed its first Judge Advocate General. At the time the expectation was that a civilian barrister would be named as the JAG by the Governor in Council but the Prime Minister opted instead to appoint a friend who happened to also be a reservist. Since that time the Canadian JAG has been a military officer.
In 1997, in the wake of the Somalia Inquiry, which clearly indicated the need for fundamental reforms to the penal military justice system, the JAG was divested of all judicial functions when full-time military judges were appointed to ensure, to the fullest extent possible, judicial independence from the chain of command. However, the JAG retained prosecutorial and defence functions, a matter of continued debate raising serious apprehension about the real independence and impartiality of those particular offices.
The JAG was also allowed the continued use of the “Judge” title which not only misrepresents the factual reality but caused it to be wrongly viewed and perceived, to this day, as the titular head of the military judiciary apparatus which is not the case.