The unfortunate flaw of democracy is that it is dependant on the dispassionate cognitive ability of the voter. Most people do not possess this. Over half of all adults never cognitively mature. Most people arrive at decisions bassackwards, their emotions dictate their choice and then they rationalize their decision, we see this all over this forum. Indeed studies show that most voters decide based on emotional influence. Politicians know this, that's why they allways blabber inane soundbites that are engineered to push emotional buttons. Also this is why Ron Paul was not popular, he tried to appeal to the voter's intellect using logic. Furthermore, most people do not trust their own cognitive abilities. If you explain some libertarian or constitutional standpoints to them they might reluctantly acknowledge that it makes sense, but then they'll say something like "yeah... but.. nah that's just crazy, you can't abolish fedral income tax." Logic is a truth that requires no searching, they can plainly see it, but they don't trust their own thinking, they defer that to the television.
Untill the majority of humans can subordinate their nature to logic, the product of national democracy will continue to disappoint.