A friend of mine is working on a book, arguing that the root problem is public votes by members of Congress. Prior to 1970 or so, Congress used secret ballots. You could lobby them but you wouldn't know whether they voted your way. A new law changed that in the name of "transparency" and corporate donations and lobbying took off in a big way after that.

We insist on secret ballots for individual voters so they can't sell their votes, but for our legislators whose individual votes are far more consequential, we've given up on it.

In exchange, we get to see how they voted and "hold them accountable." But we can't do that nearly so effectively as corporate donors. Most of us don't look at voting records at all; our information mostly comes from attack ads taking votes out of context.