Here it is taken verbatim from the brief filed on behalf of the RNC: "While candidates and political parties raise substantial funds, they are increasingly being disadvantaged and marginalized vis-a-vis super PACs, which are not subject to aggregate limits [on contributions]."

Here it is being delivered in Tuesday’s argument by Bobby Burchfield, representing Senate Minority Leader Mitch McConnell: “All the national political parties on the Republican side and the State political parties compete against each other for an artificially limited pool of money from each contributor. The same is true on the candidate side. They compete against each other for the same artificially limited pool of money.”

Here it is being parroted back from the bench by Justice Antonin Scalia during a colloquy with Solicitor General Donald Verrilli: "Isn't the consequence of [the contribution limits being challenged in this case] to sap the vitality of political parties and to encourage—what should I say—you know, drive-by PACs for each election? Isn't that the consequence?"

The issue in McCutcheon is the continued validity of "aggregate limits"—statutory maximums imposed by Congress on the amount of money an individual can give to all federal candidates and political committees in a two-year period. Currently, an individual can give no more than $2,600 to any one candidate, and no more than $48,600 to all candidates for federal office. A donor may contribute $32,400 to a national party committee, $10,000 to a state party committee, and $5,000 to a normal PAC, meaning one that gives contributions to candidates. The total per cycle is $123,200.

These “aggregate limits” were put in place to prevent “circumvention,” meaning a deliberate strategy by which a donor gives money to many sources knowing most of it will find its way to one candidate, thus breaking the individual limit for a gift to that campaign.

Of course, thanks to Citizens United and a companion case in the D.C. Circuit, SpeechNow v. Federal Election Commission, the same individual can give as much as he or she wants to a "super PAC," a PAC that spends money on political advertising without giving anything directly to a candidate. But, politicians lament, all that money flowing out into the ether! Wouldn’t it be better for everybody if it could come to ... well ... us, in the form of direct contributions to candidates and parties?

McCutcheon has stirred deep concern in campaign-reform circles—a concern Tuesday's oral argument won't do much to calm. Since the 1976 case of Buckley v. Valeo, the Court's campaign-finance jurisprudence has rested on the idea that independent expenditures (the money a person or group spends independently to promote political causes) are fundamentally different from contributions (the money individuals or corporations give directly to politicians). In Buckley, the Court reasoned that contributions—unlike expenditures on TV ads, for example—are not speech in and of themselves, but rather an exercise of the freedom to associate with a campaign. That freedom is protected by the First Amendment, but not as strongly as the freedom to speak directly. Contributions, the Buckley Court said, may give rise to “corruption or its appearance”; they may be restricted more tightly than independent expenditures.