Is a Canadian citizen who abets armed irregulars against ISAF a traitor?  
Currently ISAF/NATO multi-national forces in Afghanistan include
Canadian infantry.
If a person holding Canadian citizenship was deemed to be aiding and
abetting armed irregulars in-theater against ISAF/NATO and was
captured would he/she be a traitor under Canadian Law (ie. one who
committed treason)?

I'm not a legal expert but this seems to apply:-

Criminal Code
            PART II OFFENCES AGAINST PUBLIC ORDER
               Treason and other Offences against the Queen's Authority and Person
High treason
 46. (1) Every one commits high treason who, in Canada,

(a) kills or attempts to kill Her Majesty, or does her any bodily harm
tending to death or destruction, maims or wounds her, or imprisons or
restrains her;

(b) levies war against Canada or does any act preparatory thereto; or

(c) assists an enemy at war with Canada, or any armed forces against
whom Canadian Forces are engaged in hostilities, whether or not a
state of war exists between Canada and the country whose forces they
are.
 
From http://www.canlii.org/ca/sta/c-46/sec46.html

Para C seems to indicate that this would be High Treason.

It seems quite clear that a Canadian citizen who helps armed
combatants against whom the Canadian forces are fighting are not
guilty of high treason unless those armed combatants are a nation's
armed forces (hence the words, "...and the country whose forces they
are...").  So if a Canadian citizen helps armed terrorists to fight
against the Canadian forces, he would be guilty of an offence under
the anti-terrorism laws, but since these terrorists are not the armed
forces of any state, the citizen cannot legally be guilty of high
treason.


"46(1)Every one commits high treason who, in Canada,...(c) assists an
enemy at war with Canada, or any armed forces against whom Canadian
Forces are engaged in hostilities, whether or not a state of war
exists between Canada and the country whose forces they are."