...NO campaign financing contributions should be permitted to go into the hands of any candidate for federal office. The federal government should finance (and control the duration) of political campaigns.

That sort of law would largely, but not completely, neuter the influence of lobbyists and special interests. There is probably no way to eliminate them completely. As an example, the special interests could fund advertising campaigns of any size or content supporting one candidate or another. That is permitted under the first amendment to the Constitution.

If the candidates themselves were placed on a level playing field financially and in the length of time they can actually campaign, the American electorate would be far better informed. We could then listen to the candidates and ignore the advertisements, knowing that they were bought and paid for by special interests or lobbyists.

At least that might be a start.