The Right has complained about Unions' involvement in politics who's members vote in elections. They have tried to prevent Unions from spending any money in politics. As a Union member I have consented and voted to use designated funds politically for my interests.
To advance the Idea of one man, one vote, eliminate complaints that their money used against their wishes and to increase the democracy would be to would be to require specific permission from each person in an aggregate group eligible to vote, restricting all funds not from a consenting registered voter. That would mean every Union member, association member, club member, business owner, and share holder (business owner) would have to confirm their registration to vote and specifically assent to the use of their money for political purposes. Since Funds are commingled aggregates from many people, often retirement plans, they would not be able to separate proportions and determine eligibility, those would be eliminated as would foreign money.
No voter under this plan would be funding political causes they oppose. Restricting financial political speech to voters will involve more citizens, eliminate foreign money, and insure more accurate representation.