Read the complaint in Republican Party of Louisiana v. FEC. This is a major challenge, filed by Jim Bopp, raising not just as applied challenges, but facial challenges to the rules which limit how much money political parties can raise and from whom. And it has a real chance to succeed if the Supreme Court decides to weigh in. Much will depend upon whether the D.C. court, where this case is filed, convenes a three-judge court. If so, that means the case would come to the Supreme Court on a direct appeal and it is much more likely the Court will hear the case.
There have been two other attempts since the Roberts Court came into being. First the Court turned away an “as applied” challenge over the dissent of three Justices. Republican Nat’l Comm. v. FEC, 698 F.Supp.2d 150 (D.D.C. 2010) (three-judge court), aff’d, 561 U.S. 1040 (2010). The case raised an as-applied challenge to the soft money provisions of BCRA, and did not ask for the soft money part of McConnell to be formally overruled. Justices Kennedy, Scalia and Thomas stated that they would have noted probable jurisdiction and set the case for oral argument. See also Cao v. FEC, 619 F.3d 410 (5th Cir. 2010), cert. denied 562 U.S. 1286 (2011) (rejecting certain challenges to BCRA political party limitations).
Then, the Republican Party and Libertarian parties voluntarily dismissed cases brought, seeking a three-judge court. But then the parties, without explanation, dismissed the suit.
So it is unclear why that suit got dismissed and this one got filed. It may be because the Wagner v. FEC case makes it easier to get three-judge courts in BCRA case.
In the McCutcheon case of 2014, Chief Justice Roberts added language which seemed to invite a challenge to the soft money rules:
“When donors furnish widely distributed support within all applicable base limits, all members of the party or supporters of the cause may benefit, and the leaders of the party or cause may feel particular gratitude. That gratitude stems from the basic nature of the party system, in which party members join together to further common political beliefs, and citizens can choose to support a party because they share some, most, or all of those beliefs. … To recast such shared interest, standing alone, as an opportunity for quid pro quo corruption would dramatically expand government regulation of the political process.”
This is a big one.