Citizens United isn’t a law, it’s a shitty Supreme Court decision. It’s on the long list of obvious problems we can’t fix without first reforming the courts (I favor increasing the justice count to match the number of circuits, and also drawing the Supreme Court justices by lot for each session from the “lower” courts—shouldn’t be any constitutional issues with that approach, so it’s just a normal law, and it ought to be easier to sell than simply expanding the court and “packing” it since it’s less-partisan)

I don't know how you repeal citizens united. That decision basically fucked the US over for a very long time. I'll probably be dead before it's fixed.