OK Draug,
For one, drug lords obtain their power from operating against State's in an environment of illegality. Remove the illegality of drugs and the drug trade no longer will necessarily fall under the jurisdiction of those who are willing to fight against government enforcement (aka dudes with guns). Drugs just become another commodity, as they were for nearly all of human history without resulting in the collapse of human society.
Secondly, what is a warlord without a miniture State infrastructure? He cannot operate by himself, obvious. Your average warlord needs an army, he needs rules, he needs a justifying mandate for his power (eg. helping his henchmen or doing God's will etc.) and he needs an enforcement mechanism. The term Warlords itself is merely a way to describe dictatorships in a way that makes them sound more illegitimate by comparison.
One again, this is an example of the existence of the powerful all encompassing State being justified by the threat of even more heinous examples of coercive power.
I'm not saying that warlords aren't a legitimate threat, because they are, but it is important to note that the nature of the power wielded isn't much different. The difference is the manner in which the power is justified, and the amount of input the governed get in thier rule.
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What do I mean when I say coercive power is used unjustly? Just take a look at how drug laws are enforced in the United States. Take a look at the racial element. Take a look at how the State reserves it's right to throw citizens in jail (theoretically) for not purchasing health insurance. Take a look at how the government reserves the right to throw protesters in jail for 'disturbing the peace (hint: it just means protesting when the government isn't interested in being protested against). Take a look at how American hegemony, how European hegemony, and the hegemony of thier multinational corporations are preserved not through the righteousness or goodness of thier actions, but by thier large armies and fearsome weapons.
Most frightening of all, the leader of free world has the ability and the supposed mandate to kill anyone in the world (citizen or not), without trial, without consent from the governed, for the crime of 'posing a threat' to American interests. He has even joked about it.
I would submit that in a free society, none of the above should be allowed to occur. The only reason they can occur is because the State is so powerful and has both a mandate and ability to use force on anyone it wishes without having to justify it if it so chooses. (Nicely for us, it usually does :))
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Regarding the threat of corporations:
Note that my stance here is that because corporation won't be so large, they won't be so powerful, and they won't have government armies along with them, they won't pose nearly the same hazards. Additionally, is it so crazy to believe that were the military machines of the world disbanded for the most part, that corporate incentives for raping the earth might severely diminished?