The Bipartisan Campaign Reform Act (aka McCain-Feingold), enacted in 2002, is a landmark piece of federal legislation concerning campaign finance law. In 2003, the Supreme Court upheld the vast majority of the comprehensive scheme embodied in McCain-Friengold. However, sometimes happened to the Supreme Court after 2003, it got more conservative. Justice Alito replaced Justice O'Connor and (less significantly for these purposes) Chief Justice Roberts replaced Chief Justice Rehnquist.
Since the composition of the Supreme Court changed, the Court has consistently narrowed the application of McCain-Feingold, even more dramatically, overturned large provisions of that law. For instance, in 2010 in Citizens United, the Court invalidated a large portion of McCain-Feingold, which prohibited corporations and unions from using general treasury funds on so-called "electioneering communications."
According to a new report (click here for more from UPI), the Republican National Committee has its sights set on invalidating one of the largest remaining provisions of McCain-Feingold, the provision which limits political parties' use of so-called "soft money."