Oh Christ. Why is Citizen's United bad? All it says is you can make a political film leading up to an election and the production of that film shouldn't count as a campaign contribution. It's a perfect example of freedom of speech.

In addition it also says the PAC and politicians cannot work together. Yes, that's a valid read of the situation. But it's also naive. What Citizen's United is in reality is a loophole that allows politicians and monied people to wink at each other (without explicitly saying anything). The whole point of one person one vote in democracy is to prevent the sort of power that money and resources can bring in. A limitless amount of money pouring into elections ruins democracy. If that means a restriction on speech in a very narrow sense, so be it.

Because in practice it circumvents all the campaign finance laws that tried to somewhat level the playing field between candidates backed by the super rich and those not.

That might say more about how well the laws were written.

It’s tricky to make campaign finance laws that don’t result in censorship. If the law would have prevented someone from making and distributing a documentary ... I believe it was a documentary critical of Hilary Clinton, which is interesting ... the law wasn’t well written and could easily be abused.

It allows corporations, non-profits and labor unions to make electioneering communications. That's it.

I find it quite shocking that public service unions can spend millions of dollars electioneering for the people with whom they will be negotiating their contracts, but I'll accept the free speech rights of a voluntary association outweigh my concerns.

What public union is spending millions of dollars on elections?

American Federation of State, County and Municipal Employees https://www.opensecrets.org/orgs/totals.php?id=D000000061&cy...

American Federation of Teachers https://www.opensecrets.org/orgs/totals.php?id=D000000083&cy...

National Educators Associantion https://www.opensecrets.org/orgs/totals.php?id=D000000064&cy...

It really depends on your perspective. From one perspective, it was terrible that the least sympathetic defendants they could come up with were like Thomas Paine's great-grandsons targeted by a tyrannical FEC, so the courts really had no choice but to throw out the terrible law. From another perspective, it was really convenient that all the rhetorical noise and political effort that went into McCain-Feingold could be neutered so easily. Why did Deputy Solicitor General Malcolm Stewart really start out with such an absolutist argument? The "even one sentence" formula was fairly shocking in that context, but the public may never know why he used it...

Do you have a link to General Malcolm Stewart's argument? I'd like to read up on it to learn more about this perspective.

Sorry to take so long. The following contemporaneous NYT article discusses the argument, but it doesn't contain the phrase "even one sentence". It does give a flavor of the justices' skepticism at the absolutism of the deputy solicitor general's argument:

https://www.nytimes.com/2009/03/25/washington/25scotus.html