I want to get a generally benevolent party to unwittingly further the villain's motives. More than parcel delivery – I'd like to tap into their sense of right/wrong, justice, vigilantism, what-have-you. My idea for this is for the villain to be some sort of mobster and they'd recruit the characters to 'punish some bad guys,' when in actuality all they'd be doing is harassing his enemies and executing his dirty work. Think late '60s and early '70s CoIntelPro.
How can I get them to see what they're doing as good?
How can I get them to remain jaded against reasoning with their 'bad guys?'
Lastly, how can I maximize the chances that they won't catch onto the villain's plans, and thus keep them in 'pawn' status as long as possible?