Four years after the Supreme Court deregulated independent campaign spending in Citizens United v. Federal Election Commission, the high court is poised to yet again turn American elections upside down.  

The court is expected to rule any day now on McCutcheon v. FEC, another potentially landmark constitutional challenge that could shake up campaign financing as dramatically as Citizens United did in 2010. While no one can predict how the court will rule, oral arguments in October suggest that conservatives in the majority remain as eager as ever to dismantle money limits.  

At issue in McCutcheon is the constitutionality of existing overall limits on how much a contributor may give to candidates and political parties in a single election cycle. Alabama businessman Shaun McCutcheon, who brought the challenge, argues that the $123,200 cap on total contributions per cycle violates his First Amendment rights.  

The limit’s defenders say that tossing it out will bring back the “soft money” days when donors freely wrote large, unrestricted checks to the political parties. That soft money, banned by the 2002 law known as McCain-Feingold, was raised by the elected officials who ran the parties — and wrote the bills that the big donors lobbied for and against. It was an invitation to abuse, a parade of lawmakers and donors told the court when it took up McConnell v. FEC, the constitutional challenge that upheld the soft money ban in 2003.  

But the Supreme Court has partially changed hands since then, and today’s right-leaning justices appear to have forgotten that unrestricted, multimillion-dollar contributions to the political parties ever drew fire. In Citizens United, the high court concluded that unlimited campaign spending by unions and corporations (including incorporated nonprofits) can’t corrupt anybody when the spending is independent — not coordinated with candidates or parties.  

Now some on the court argue that big money should be legal for political parties as well. As Justice Antonin Scalia told Solicitor General Donald B. Verrilli Jr., during the McCutcheon oral arguments: “It seems to me fanciful to think that the sense of gratitude that an individual Senator or Congressman is going to feel because of a substantial contribution to the Republican National Committee or Democratic National Committee is any greater than the sense of gratitude that that Senator or Congressman will feel to a PAC which is spending enormous amounts of money in his district or in his state for his election.”  

Never mind that this argument undercuts the court’s own conclusion in Citizens United: that independent spending poses no corruption risk because politicians are not involved. A ruling in McCutcheon’s favor might well free up elected officials to collect unrestricted soft money for the political parties once again. That’s because without the aggregate limits, politicians in charge of joint fundraising committees could ask donors to write checks of as much as $2.5 million or more at a pop, advocates of campaign restrictions argue.  

A ruling for McCutcheon would also weaken the “base” contribution limit, a cornerstone of the remaining campaign finance rules. That limit bars an individual, for example, from giving a candidate more than $2,600 per election. Historically, the court has held that limits on contributions are less of a First Amendment burden than restrictions on spending. The McCutcheon challenge argues, in part, that contribution and spending limits should be treated as equally onerous. If the court agrees, a successful challenge to the base limits could be next.  

“This case not only threatens to have a broad impact on laws limiting aggregate contributions, but could also, depending on the scope of the ruling, jeopardize even the longstanding ‘base’ limits on contributions to candidates and political parties at every level of government — municipal, state and federal,” warns a background memo circulated by the Campaign Legal Center.  

The center is one of several watchdog groups bracing for a McCutcheon ruling that may well deal another blow to campaign finance restrictions. Public Citizen has also released a two-part “prebuttal” to the pending McCutcheon ruling titled: “Beware of a Naïve Perspective.”  

When Justice Anthony M. Kennedy wrote the majority opinion in Citizens United four years ago, he asserted blithely that the Internet age would ensure enough “prompt disclosure” to hold corporations and politicians accountable. Nonprofits exempt from the disclosure rules, such as social welfare and trade groups, went on to spend more than $300 million on the 2012 elections, all without disclosing a single donor.  

The question now is whether the high court, having freed outside groups to spend record sums of unrestricted soft money in campaigns, will also extend that invitation to political parties — and the politicians who run them.