Brendan McDermid/Reuters

“Aggregate limits [on campaign contributions] combat corruption,” Solicitor General Donald Verrilli told the Supreme Court in the case of McCutcheon v. Federal Election Commission this week. But never did he explain—in a way that this Court could understand at least—just how. The risk of removing aggregate limits, he insisted, was an illegal “quid pro quo.” Yet if each individual contribution within the aggregate falls below the legal limit, how does adding them all up somehow render them corrupt?

The closest the government came to answering that question was a single passage buried in the middle of the argument. “If you take off the aggregate limits,” the government argued, then “less than 500 people can fund the whole shooting match, [with] a very real risk that the government will be run of, by, and for those 500 people.”

That number is a bit exaggerated. We’re never going to have a system in which just 500 people fund the elections of 535 senators and representatives. But multiply that number by 50: Imagine 25,000 people funding “the whole shooting match.” The question remains: why would that be “corruption,” so long as none of the 25,000 gave any individual candidate more than the individual maximum amount?

If “corruption” means just an illegal “quid pro quo,” that indeed is a very hard question, as the solicitor general discovered this week. Yet for an “honest originalist,” as Justice Antonin Scalia recently described his judicial philosophy, and presumably, the philosophy of the other four originalists on the Supreme Court, there’s a pretty obvious reason why a system in which Congress is dependent upon 25,000 individuals would be a “corruption.”

“Corruption,” according to the Framers of our Constitution, did not mean just, or even primarily, the “quid pro quo” corruption of individuals. Instead, as an empirical study of the Framers’ usage reveals (and as I argued in an amicus brief in the case) the dominant conception of “corruption” for them was the corruption of institutions, not individuals. Fifty-seven percent of the times when the Framers used the word “corruption,” they were speaking of institutions. The one clear and repeated example was an institution that had developed an “improper dependence.” Parliament, for example, was corrupt because it had developed an “improper dependence” upon the king. The key to fighting corruption, then, was to avoid such “improper dependences.”

This conception of corruption is directly relevant to the question of aggregate limits. According to Madison, Congress did have a dependence—but in this case, it was not improper, it was intended. As he wrote in Federalist 52 (in a passage that Scalia quoted just last Term), the House, at least, was to be “dependent on the People alone.” Alone. An exclusive dependence, not one among many, and as Madison wrote in Federalist 57, “not the rich, more than the poor.” (The Senate was different, because it was appointed by the state legislatures.)

Removing aggregate contribution limits obviously weakens this intended dependence. Once aggregate limits are removed, the business model of fundraising shifts to an even stronger focus on large contributors. The concentration of funders would then increase; Congress’s dependence upon a shrinking number of funders would also then increase. Removing aggregate limits would thus corrupt the “dependen[ce] on the People alone” that the Framers intended—or at least, so an “honest originalist” could well believe.

Consistent with Citizens United, no less. Recognizing “dependence corruption” as a kind of corruption that would empower Congress to act would not undermine the holding in Justice Anthony Kennedy’s opinion in Citizens United (a decision that Justice Elena Kagan clearly signaled her desire to overturn). In my view, the non-profit Citizens United should without doubt have been free to spend its money to promote its film. That speech had nothing to do with either quid pro quo corruption or dependence corruption. And thus an originalist following the Framers’ view about “corruption” could do so consistent with the vote to protect Citizens United’s speech.

Yet it is a measure of the pervasive partisanship that is Washington today that it doesn’t even occur to Obama’s solicitor general to suggest a politically conservative argument to Chief Justice John Roberts's Court that, if applied honestly, might well yield a politically liberal result. That may reflect a limit in the imagination of the Obama lawyers, or a simple realism about the ideological rigidity of this Court. Either way, it is astonishing. Rather than advancing the one argument that the five originalists on the Court might be able to hear, the government insists on standing with an argument that all five conservatives on the Court have already rejected. And so the government leads the Court to do what most Americans expect it will do anyway: Confirm an ideology, rather than honestly follow a principle that might well track something other than simple ideology.