Dennis Gorelik

Election system needs to be simple and fair.
That is why in a democratic elections -- one citizen has one vote.

However there is a problem with "one person - one vote system": there are a lot of poor citizens with voting power who do are not able to manage their personal finances well. If elections were completely fair, then this poor majority would define how country's economic system runs. The end result will be similar to what Venezuela has right now (oil-rich country has struggles with even getting food and electricity, thanks to the socialism that breaks Venezuela's economy).

In order to prevent catastrophic economic decisions, more government power should be transferred to the people who understand how to manage the economy better -- the relatively small group of rich people.

One way to do that -- would be to elect the government -- proportionally to how much taxes a person pay to the government (private corporations elect their corporate boards in a similar way). For example, $10,000 in taxes that a household paid in the last 4 years prior to the election -- would represent 1 vote.

But such strong "taxes -> government power" link will lead to a lot of people who do not pay taxes (or pay very little taxes) to have almost no representation in the government. Such powerless situation frustrate people. Collectively, poor majority still has a lot of "people power" even though they do not have money. "People power" should have a legitimate representation in the government.

The adjustment "taxes power" solution is to mix in "people power" solution.
So every $10,000 paid in taxes would get 1 vote, but also every person would get a vote.
I, personally, am in favor of such mixed "taxes power + people power" system. But such mixed system is too complex to understand for most citizens.

So most democracies (including the United States democracy) evolved to apply "corruption" fix to their democracy.
"Taxes power" is substituted with "corruption power". So now rich people can sponsor politicians in order to influence the outcome of the democratic election and get some power back from economically clueless majority.

Unfortunately, corruption has a lot of negative side effects. For example, it may be very tempting for a business to spend $1M kickback on a politician in order to get $10M in form of government handouts. In well-functioning democracies (such as the US democracy) kickbacks are illegal.
But some forms of corruption are explicitly legal. In particular, it is legal to sponsor politicians' campaigns, so the corrupting money will be spent on convincing the voters to support the politician. That form of corruption results in brainwashing campaigns which may also have some negative effects, but these negative effects are not nearly as bad as negative effects from kickbacks.
If corrupting sponsor-politician deal is too bad -- the brainwashing campaign will not be able to convince the voters to accept the bad deal (at least not in a society that respects a free speech).
And even if brainwashed majority accepts a bad deal, they do NOT riot against it, because they had a chance at election to reject that deal, and have another chance at the next election to reject that bad deal.

To summarize:
1) "Sponsoring election campaign" form of corruption is a practical way to improve performance of a pure "people power" democracy.
2) "Sponsoring election campaign" corruption still has significant disadvantages, but these disadvantages are not nearly as bad as allowing economically clueless majority to run the country unchecked.
3) It is possible to setup a well-functioning democracy without legalizing any corruption at all, but the alternatives (such as "taxes power + people power" system) are more complex than existing "1 citizen - 1 vote" election system.