http://definitions.uslegal.com/c/complicity/Complicity in criminal law refers to when someone is legally accountable, or liable for a criminal offense, based upon the behavior of another. Criminal complicity may arise in the following situations:
With the intent to promote or assist the commission of the offense:
1. a person procures, induces or causes such other person to commit the offense; or
2. a person aids or abets such other person in committing the offense; or
3. having a legal duty to prevent the commission of the offense, a person fails to make an effort he is legally required to make.
I think a very wide case can be made against many parties, from individuals to countries, that by any measure are complicit in crime, such as murder.
To set the spectrum wide enough: from a country selling arms to Israel that acts disproportionally by killing hundreds of civilians in Gaza and South Lebanon... to friends and family that shelter, encourage and bless Palestinian suicide bombers blowing up buses and restaurants killing dozens.
It would seem that complicity in such a violent arena where everybody is at each others throat is a moot concept but if one is to judge a country, group or individual as complicit in murderous crime one should stay out of it, for starters. The "Milo doctrine" looms heavy.
I was just curious what in, say, the USA happens to somebody proven complicit in a crime like murder matching one or all of the 1), 2) and 3) criteria.