This discusses some basic concerns about whether democracy is a good idea. I happen to think it's a really bad idea, so I find these worth talking about.
Incidentally, although the post is right to say that Plato was suspicious of democracy, at least in Republic (not so in Laws), some of the history isn't right. Plato wasn't killed by a mob, but instead suffered more under tyrants. He died, apparently of natural causes, at his Academy. Aristotle liked democracy, but he didn't call it "democracy". What he calls "democracy" is something like mob-rule; his "republican" government, though, is democratic in a more general sense. For Kant's views, see Perpetual Peace. I don't recall what he thought of democracy, but given that he was a big fan of the choices of individual agents, vis-a-vis respect for the moral law, I'd suspect he'd generally be in favour of something at least democratic in character.
The first is the idea that there is a "natural aristocracy" which "should" govern. This is actually Plato's gambit in Republic (but, interestingly, not in Laws). As one should have one's shoes made by a good cobbler, one's polis should be led by a good leader. As Popper pointed out, though, in The Open Society and Its Enemies, that choice of question is loaded in favour of that kind of answer. If you start out with a different question -- Popper's favoured one is "how can we best prevent tyranny?" -- then you should end up with a very different answer.
That's all well and good, but it doesn't really address what's wrong with the question. I find two problems with it, both deriving from the idea that the aristocracy is "natural": first, the aristocracy is unchangeable and, second, that it is good. The former is simply false. Nature changes all the time. That should be incredibly obvious.
The latter is the naturalistic fallacy: just because it's natural doesn't mean it's good. These are different orders of claim: the former is descriptive, about what exists, while the latter is normative, about what should exist or what it would be better if did exist. Reading one order of claim off from another order is fallacious thinking because it ignores the difference.
There's also a real problem in claiming that there's any such thing as a "natural" advantage in something as contextually dependent as leadership ability. It's at least highly suspicious to say that people are just made into ideal leaders. It seems more plausible to say that people can become good leaders, given appropriate influences, education, opportunities, etc.
That, really, is an argument in favour of democracy in an ideally-functioning society. If you have a vast mass of well-educated people who have come under good influences, who are generally well-off, etc, etc, then you have a number of potentially ideal leaders. Any of them could stand for office, and any of them could rationally (by definition) appoint a representative to office in their stead. (It's even conceivably possible that, in such a society, representatives may not be necessary and democracy could be direct.)
Of course, we aren't in an ideal society. We're in a society largely composed -- and let's be fair to them -- of idiots. Or, to really be fair to them, of hedonists. As long as their immediate pleasures are satisfied, they don't care about anything else. Only on the most bizarre theory of the good is it the case that people like this constitute a "natural aristocracy". So, while warding off tyranny in the long run may be a good thing, it strikes me that periods of limited tyranny, to force an indolent society back "on track", are not something that should immediately be dismissed as "bad". Indeed, they may be necessary. (One of my favourite historical factoids is that, before the institution of their version of democracy, Athens was ruled by a benevolent tyrant, Peisistratus.)
The post also discusses some problems with democracy:
(2) Tyranny of the majority
(3) Idiocy of the majority (dealt with above)
(4) Security of voting
(6) Imperfect information
(7) Myopia (focus on the short-term)
(8) Winner takes all
(1) and (2) look like the same problem, but from different angles. If you have a system that encourages groups of people to band together in order to wield political influence, there is always a significant risk that this will degenerate into the rule of a "mob" or a situation where a majority group can ram through laws that are disfavourable to the minority. Limited powers is one attempt to block this situation: if governments are simply not allowed to do certain things (e.g., violate the rights in a constitution), then the situation is somewhat alleviated. Checks and balances or distribution of powers are another: if no one group in government can do whatever it feels like, then the amount of influence required to ram through laws becomes greater -- hopefully, sufficiently great that it is practically impossible to achieve it. Neither is a perfect solution, but democracy, by its nature, is an imperfect system, prone to degeneration. (In this, I agree with the basic idea of Plato's cycle of styles of government, discussed in Republic. No system of government is stable enough to last forever.) They'll work for a while, then the system will collapse and, hopefully, renew or improve.
(4) through (8) look like procedural problems, though, rather than issues with democracy in itself. (4) can be fixed through paper balloting. (5) can be fixed through rigid financing laws, that are actually enforced. (6) can be similarly fixed, by holding officials accountable for breaking their word and the like. (7) could be fixed by either extending terms, or staggering elections to ensure that some group in government has continuity over time, and so on. And (8) is contingent on particular election procedures.
The post also suggests that we should research candidates before voting. I'd go a step further and suggest everyone should run for some kind of office. If you really don't like your government, complaining about it is simply weak, as is standing in a booth for two minutes and checking a few boxes. The only way to really get a government you're happy with is to actively try to become a part of it. Voting is really less fundamental than the right to be a part of the government. After all, the very idea of democracy is that we are all self-governing, and government above us is only legitimate if we grant it the power to be legitimate. So, since we already have the power to govern ourselves, why not use it in government?
There's a closing quick ding at intellectuals not running for office. I think this may be an American problem, but it's worth wondering about what it is that makes American elections prone to being ignored by people of intelligence. (Or, at least, people who are willing to admit to being intelligent. Clinton, for example, was a Rhodes Scholar and has a J.D. from Yale Law -- so, no dummy there. Yet, I can't recall that information being part of his election campaigning.) I'd suspect a general cultural playing-down of intelligence, but that does exist, to some degree, in other parts of the world as well. So, if it's explanatory, it's only going to explain a detail or explain in a derivative fashion.
I don't know what more fudamental aspect of the US culture or its political system may be fueling this problem, though. It could, I suppose, be a purely materialist explanation: intellectuals don't tend to be rich enough to run for the most important public offices in the US. But this sounds quite weak to me, as there are any number of quite personable US academics who could, in principle, wine and dine in order to raise funds just as the current politicos do. So, I'm tempted to think the explanation must somehow be ideal -- there's something in the culture that discourages intellectuals from public life, or that encourages non-intellectuals into public life -- but I have a hard time putting my finger on it. Perhaps simply that public life isn't valued very much in the US? And those who have something else to do, such as intellectuals, are considered to be better by doing it?
I note with interest, though, this blog post about philosophers starting to engage in the public sphere. I think that the pressures which tell against philosophers stepping outside the "tower" and speaking to the rabble should be the same as those which discourage intellectuals in general from contesting for public office.