A republic/democracy is like any other form of government. It empowers one political group over another. There is no permanent title. Your neighbors can always take your property away. This creates a disincentive to "own" and an incentive to use the political means to take someone else's property. The final stages of democracy are a race to the bottom (like we are beginning to see in Greece, and soon in the US).
In a monarchy, the King is judge in his own case. In a democracy, the majority are judge in their own case. Nothing good can come of this arrangement. Besides what I mentioned, democracy should be abolished for these 3 major reasons:
1) Conflict with Self ownership: Taken by many to be axiomatic. I use the standard of universalization to judge among competing theories of ownership. Thus, some men cannot own themselves and others (democracy). There are other ownership patterns, but self ownership is the only universally consistent position.
2) Moral Hazard: The majority gets to decide which rights citizens have. There is no check on majority power that the majority cannot overcome. Theoretically and in practice, this leads to predation and exploitation of minority classes who have no recourse. This has many detrimental economic and moral consequences.
3) Voting is a Collective Action Problem: Each individual's vote has a very low chance of deciding elections. As such, voters are rationally ignorant. Political positions are chosen not on the basis of any real merit, but for fashionable/self validating purposes.
This is what opens the door for special interests like the banks & corporations you mention. Say for example there is a piece of legislation that would cost each voter $1, but benefit some special interest group $1,000,000. If a voter spends an hour of his time trying to fight the special interest, he is working for $1/hr. The special interest group will lobby much harder to get the legislation passed. Rinse, repeat, democratic failure.
Anarchy isn't the cure, anarcho-capitalism is. Anarchy is when there is no state. Anarcho-capitalism is when there is no state but there is private property rights. A society can be slow to develop private property rights even without a state.
"I hate government as much as government hates freedom, and that's a lot." - Mike Malin
Check out my PowerPoint: http://www.slideshare.net/anarcholibertarian/why-do-they-hat...
And my Ron Paul vs. Lincoln video:
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