Legal terms I've come across.
Amicus Curiae.
Amicus curiae (plural amici curiae) is a legal Latin phrase, literally translated as "friend of the court", that refers to someone, not a party to a case, who volunteers to offer information on a point of law or some other aspect of the case to assist the court in deciding a matter before it.
-Wikipaedia
Well, not much to add to that, really. The Cambodia Daily refers to them as "friends of the court" and my legal scholar friend calls them "The Amicis". There aren't too many places that open invitations are given for Amici Curiae briefs because in places that speak English as a result of British colonisation English Common Law was automatically inherited into the court system, giving more precedent than could comfortably be used.
Precedent.
Noun /pressid'nt/ 1 an earlier event or action serving as an example or guide. 2 Law: a previous case or legal decision that may or must be followed in subsequent similar cases.
- askoxford.com
"A precedent embalms a principle."
Lord Stowell 1745 - 1836: an opinion, while Advocate-General, 1788, quoted by Disraeli in House of Commons, 22 February 1848
- askoxford.com
Common Law
Noun law derived from custom and judicial precedent rather than statutes.
- askoxford.com
Statutes
The law as enacted by parliament/national assembly/congress.
...back to the Amicis...
The information may be a legal opinion in the form of a brief - testimony that has not been solicited by any of the parties - or a learned treatise on a matter that bears on the case. The decision whether to admit the information lies with the discretion of the court.
- Wikipaedia
The Courts in Cambodia do not have a complete record of common law decisions. Some was destroyed by the KR. Some laws have been repudiated due to changes in government and constitution.
Repudiate
Verb 1 refuse to accept or be associated with. 2 deny the truth or validity of
- askoxford.com
Laws can also be expunged.
Expunge
Verb obliterate or remove completely.
- askoxford.com
The Judges in Cambodia do not have complete legal educations. Again, civil war/KR/changes in regime can be traced as the route cause.
Plus, the ECCC is operating under a relatively unique hybrid of local and international law. It's not too often that international law is quoted in Cambodian court rooms. Meaning the judges have their work cut out for them when it comes to interpreting the law if they first have to learn it all from scratch within a week.
Which is where the Amicus Curiae comes in. If you're a judge at the ECCC and you have a limited staff of clerks to help you with research, why not delegate the task to qualified outsiders with knowledge of such things as the Nuremberg statutes and the Geneva conventions and declarations? All you have to do is call for Amici Curiae and wait for the fools, such as my legal scholar friend, to do your work for you.
The Amicus Curiae will mine through international statutes and precedent, writing a, hopefully, reasoned, cogent legal argument in favour of either of your two choices complete with references to "a previous case (or cases) or legal decision that may" apply to the case you are hearing.
In the case of Duch, Duch's lawyers quoted from the ICTR (International Criminal Trial for Rwanda). Co-prosecutor Robert Petit referred to this during spoken testimony as the "Defence...arguing against itself by relying on such jurisprudence."
Petit should know (theoretically) as he was a co-prosecutor in Rwanda as well.
Duch's appeal against provisional detention focused on his eight years or so in military prison in Phnom Penh without trial.
The case for the prosecution rested on the fact that the military's case against Duch is completely separate and if he's unhappy with his detention by them then he should file an appeal with them.
In Petit's words
"Nowhere is it stated the ECCC has primacy over any domestic court."
and
"In our case, the military court did not detain the charged person under lawful process pursuant to the procedures of the ECCC."
After taking into account the views (and legal arguments) of the defence, the Co-investigating judges, the Co-prosecutors and the Amici Curiae, the judges agreed with Petit and told Duch to look forward to a continued stay as a guest of His Majesty and the Secretary-General.