We learn from history that men (well politicians) never learn from history. Prohibition was a miserable failure, so we repealed the 19th amendment, but continued the war on drugs. We can pass laws limiting campaign financing, but it is naïve to think that will make it go away. Like any other popular activity outlawed, it will find ways to go underground, out of sight, totally unregulated and dominated by organized crime.
I cannot think of a prohibition that accomplished its goal, can you?
Maybe contributions could be double blind.