Yes, Citizens United made it explicit that money is speech and as such can't be hindered. I suspect that because of this ruling, we couldn't just pass a law that prohibits money in politics because the ruling precludes it.

A constitutional amendment would nuke the current limitations, but it's impossible in practice for us to get there. On the other hand, as we've seen as of late, no decision by the Supreme Court is set in stone, so we could, in theory, get Citizens rolled back and then some. That also seems unlikely in the short term.

Congress could fix it if they really wanted to. Make a law that essentially reverses the interpretation of Citizens United, and then take it out of the jurisdiction of the Supreme Court.

Not that this is in any way likely to happen, of course.

If such a law were passed (and I agree, it's extremely unlikely), I expect that litigation would be filed as to it's constitutionality. Which would put the ball back in the Supreme Court's court, so to speak.

I'd like to see how that would work. In the past, SCOTUS has acknowledged that the Constitution indeed grants Congress the ability to remove legislation from the court's jurisdiction.

Notably, the Constitution does not grant the court the power of judicial review. The court granted itself that right. So in a battle between precedent and the text of the Constitution, I hope the latter would win.

While this is the common shorthand, what actually happened is pretty different. The ruling is people don't lose their rights when acting as a group. John Smith, Girl Scout troop#2365, and Bank Of America are all equally protected to create and publish a Pro or anti politician message. There isn't really a law that can just say money isn't speech, because that doesn't change anything.