A year ago this week, the Supreme Court issued a ruling so momentous that many are still grappling to take stock of its impact on our political system. The case: Citizens United. The decision: In a 5-4 vote, the Supreme Court ruled that it was unconstitutional to limit in any way the amount of money corporations can spend on attack ads or other “electioneering communications” to sway a political race. The decision opened a massive loophole in our country’s already-porous campaign finance system, giving corporations the green light to inject unlimited sums of cash into independent groups that can intervene in elections.