What was the impact of Citizens United vs FEC on the impact of corporations funding politicians in the United States?

Citizens United vs Federal Election Commitee (FEC) was critical in enabling corporate funding from poorly disclosed sources under the 1st amendment. The Supreme Court blocked the motion from the FEC to restrict Citizens United on releasing a 90 minute documentary that was funded by corporate interests with a perspective and directive of voting against Hilary Clinton. The proximity to the election coming up made the FEC weary of large monied interests having a stake in public discourse and electioneering.

Citizens United ultimately won this case, and it has opened the floodgates for Billionaires to fund certain Super PACs (Political Action Committees) and has made it very hard to get large corporations out of Washington DC and Congress, which ultimately has undermined the will of the American public across the political spectrum.