I've been thinking about your AP idea, and think rather than make mock contracts on political "targets", which is a bit incendiary, one could make headline "bounties" that, if met, get rewarded. Like "CIA director, X, dies from food poisoning".
One possibility would be to implement an AP system, but limit the payout for any one target to a fairly low value, say $1000. (enough to cause a bit of worry). Then file a lawsuit in Federal Court for an injunction against law enforcement authorities to demand that the legalities of such a system be debated and declared. 'They' would have to explain and document why they thought that such a system was illegal, or admit it would be legal.
Having payouts is pretty risky, because they could claim that you aided or abetted a criminal act, but the beauty of using headlines is that you don't have to suggest that anybody get hurt. You/US have to be creative. It puts equal burden on the headline maker to think of something that gets *righteous* payback without actually hurting anyone. AND you get the added bonus of complete separation from the act. I shouldn't have used the example of a CIA director dying of food poisoning, because that could be construed as incentivizing murder (especially if you're offering payouts). I think in the end, the right way to handle this is to think creatively and not use assassination as a model at all, but keep the payout bounty idea. People just have to be more creative at getting payback. Marxos