One key principle that a lot of people miss is that quadratic voting doesn't work with real money because people don't value wealth in a linear fashion. $5 is worth much more for a homeless person than for a millionaire. Proof of this can be seen in preference surveys or other studies of human behavior. This fact breaks the key assumption of quadratic voting and causes skewed results in that people with more money can buy more votes even with "weaker" preferences.
This is addressed in the Wikipedia page under "Criticisms of quadratic voting mechanisms".
Potential solutions include giving everyone the same amount of starting artificial "money", using one-person-one-vote when issues are polarized along wealth-lines, or making votes more expensive for the wealthy.
To me, the first option of delegating everyone the same starting votes seems the most reasonable. However, I think allocating vote prices based on wealth could create some interesting incentives and resulting politics.
What the wikipedia criticism doesn't mention issue flooding/packing. Quadratic voting works, on paper, when applied to set piece issues. It doesn't address the reality of legislatures, that "issues" are not fixed pieces on a chessboard. Issues can be split across multiple referendums. Whoever is in control can use splits to dilute votes, causing voters to spend their votes repeatedly winning a minor issue until their are depleted. Then those who 'lost' the first rounds now have the votes to win the last round. Giving everyone equal footing on every vote stops this.
I had the same thought. This system does not account for the introduction of legislation that can be voted on. Who decides which legislation to consider. Surely the party in power could sway the outcome by stacking the decions against each other.
This is equivalent to gerrymandering political districts. Spread out the votes on the issues based on the electors in favor of a predtermined outcome.
That's essentially the solution to this problem. Or you can think of it another way. Every person gets x votes (we'll say 100, but it should probably change dependent upon the ballot, which can get confusing but we'll ignore that). You can go all in on one candidate and designate all 100 votes to that one, but you forfeit voting elsewhere. Like on the general election ballot you will have the president, senators, congressional rep (what's the preferred gender neutral term?), governor, etc. You can assign all 100 votes in the presidential race and forfeit voting in the other races.
Of course, this brings a difficult problem on a national scale. Often many seats are run uncontested, even in large areas. So if we had a minimum of 1 vote per candidate, that would give certain areas and certain elections more power. You could then "hack" the election simply by running extra candidates and make it seem more contested. While I like cardinal systems, I think quadratic gets extremely complicated as soon as you try to expand it outside of a localized election and maybe it isn't worth it.
