Was the US known for oppression of ideas prior to Citizens United? I'd actually argue that the ruling has made speech less free in the US because now the rich are better able to outshout those with less money, while simultaneously increasing corruption in the political system.
Citizens United is unfortunate, but I personally worry more about paid lobbyists.
FWIW - I used to worry more about paid lobbyists too. But superpacs have (smartly) increased the scope of the strategy all the way down to tiny local races and it is WILD to see in person.
Here is my anecdote: During our last election cycle Freedom Works held events in my town that were co-located with v. conservative candidates running for school board.
At first, a lot of us wrote the v. conservative candidates off. They had just moved to town within the year, no one knew who they were, neither of them had children who attended our schools. They were running against a local mother who was a former teacher, current high school band volunteer, active member of the community and had a PhD focusing on special ed. She was a shoe-in, until she wasn't.
The Freedom Works related folks held workshops on how to protest CRT and mask requirements, and a few days later our school board meetings were shut down with protestors. Some of us started to notice the flood of political supporters for the candidates in our town facebook group. The conservative candidates ran targeted facebook ads and robocalls and filled our mail boxes and front doors knobs with materials. They were everywhere.
FWIW - I have never in my time in this town received materials for someone running for the board - I went to the debate and met them when they walked around my neighborhood. So this was new and different.
It took an exhaustive, labor intensive social campaign in the last three weeks of the election for the local candidate to eek out a win by a few points. And it was basically local, working parents (mothers) on zoom at 11pm frantically coming up with with free and "easy" ways to point out how bad the two newcomers were. But I guarantee we wouldn't have the time or energy (and already didn't have tens of extra thousands of dollars to spend) to keep this going long term.
Parents with work and kids have a hard time competing with funded candidates. As a person who cares deeply about politics, it has been one of the hardest things for me to accept - that there is so little I can do.
(FWIW I also think the "working a w2 job w/kids" thing and general demographics contribute to the candidate gap we see in down ballot races when looking at Rs vs Ds.)