In an indirect way that happens in some politics. Parties and political figures need funding, they get that funding from organisations and individuals with deep pockets. Even if politicians argue that their policies aren't influenced by donations, donors aren't going to fund someone who promotes policies which the donors don't agree with. And given how expensive it is to run an election campaign, politicians with unpopular policies a (amongst the wealthy and big businesses) will either risk exposure due to poor funding, thus potentially lose votes, or "soften" their policies to appeal to the deeper pockets. Either scenario results in a subtle bias towards big money.

I wouldn't like to speculate on how significant this bias might be though, nor would I know how to level that particular playing field. Maybe everyone donates into a central pot and campaigners all get an equal share of the pot?

Maybe you should think it through...

That would heavily favor the high-income voters though.