The U.S. Supreme Court is hearing oral arguments today in a major campaign finance case that is being referred to as “the next Citizens United.” The case, McCutcheon v. Federal Election Commission, could undermine most of the remaining rules curbing massive spending by wealthy donors. Currently, individuals can spend no more than $123,200 directly on candidates, political parties and political action committees in a single two-year election cycle. That cap includes a limit of $48,600 on direct donations to candidates. But the Republican National Committee, Senate Minority Leader Mitch McConnell and Republican businessman Shaun McCutcheon want the Supreme Court to throw out the aggregate limits, saying they violate free speech. The case marks the first major challenge to campaign finance rules since the 2010 Citizens United decision, which opened the floodgates for unlimited corporate spending on elections. In a statement, longtime campaign finance advocate Fred Wertheimer said repealing the caps at stake in the McCutcheon case could “recreate the system of legalized bribery that existed prior to the Watergate campaign finance scandals.”