There's a difference between me telling you my opinion on an issue and me knowingly spreading false information at a mass scale for personal gain. I think that specifically (in my layman's interpretation of law) does not fall under the first amendment's interpretation of allowing freedom of expression since the expression is not genuine, in the same way that fraud is not genuine. You would not be prosecuted for fraud for unwittingly spreading false information, but you would be for doing so wittingly and with incentive for making money

Why are you assuming that the information spread is false? Propaganda is not necessarily false, in fact, it is better if it is true.

Platforms like Facebook would be well within their rights to try and prevent politically targeted advertising, even if it would be a fool's errand. Outlawing it would be unconstitutional.

If they try to prevent "spreading of false information" by political advertisers I've no doubt they will simply be harsher on the propagandists who have a political aim at odds with Facebook's interests, one of which is stopping these hit pieces by those angry that Trump won.

Nobody would be talking about this if Cambridge Analytica worked with Hillary. They simply want to stop their opponents from using the useful tool that is targeted advertising.

First, I agree propaganda is not always false, but if you read a post I made earlier, you'll see that the reason's it's a problem is that it controls narratives and creates curated biases that give people inaccurate beliefs (e.g. by focusing heavily on single small issues to further a controversy). For example, consider that Russia created fake BLM-related twitter accounts to stoke tensions and drive controversy on both sides of the issue: http://faculty.washington.edu/kstarbi/examining-trolls-polar.... This is somewhat different, less propaganda and more astroturfing, but the effect is the same regarding propaganda: to direct the narrative into something convenient for those behind the strings.

Outlawing political advertising is not what I propose. I believe propaganda is different in its intent: in my opinion direct disinformation or dishonesty (with intent) would be a sufficiently high barrier, given that it would require a high barrier of proof that the supporters were seeking to manipulate opinion with lies. This would ensure nobody would be prosecuted except in the most egregious of cases. I also believe this could be a valid exception to the first amendment in the same vein as libel or slander: spreading false information, with intent, possibly for personal gain. The parallels certainly exist.

Furthermore, I believe I would be just outraged if Hillary did this, and I think this is a pointless distraction. I didn't vote for her and I know that she also had her own shady internet propagandists working too. I think we should do our best to make sure political discussions happen organically, from real people.