On “Fox News Sunday” yesterday, Chris Wallace asked Senate Minority Leader Mitch McConnell (R-Ky.) about Republicans refusing to allow lawmakers to vote on Richard Cordray’s nomination to head the Consumer Financial Protection Bureau. The GOP Senate leader wasn’t the least bit embarrassed about his party’s abuses.

“[W]hat we are saying to the president is: join with us and reform this agency, make it accountable to someone, the people elected the Congress for its funding and for its oversight, and then send up somebody and we’ll be happy to confirm them. There’s nothing wrong with Mr. Cordray personally. This is about an unaccountable, unelected czar. And we’re simply not going to appoint him, or confirm him, or anybody else to this agency that shouldn’t exist in its current form.”

Note, McConnell said the bureau “shouldn’t” exist. That it already exists is, to him, irrelevant.

Around the same time, on “Meet the Press,” David Gregory asked Sen. Lindsey Graham (R-S.C.) about the same controversy.

“So this consumer bureau that [Democrats] want to pass is under the Federal Reserve. No appropriation oversight, no board. It is something out of the Stalinist era. The reason Republicans don’t want to vote for it is we want a board, not one person, making all the regulatory decisions, and there’s no oversight under this person. He gets a check from the Federal Reserve. We want him under the Congress so we can oversee the overseer.”

All of this may seem rather routine — Republicans have been making the argument for a while — but it’s worth pausing to appreciate just how radical a position this really is.

Graham, who really ought to know a little more about current events, characterized the Democratic position as eyeing an consumer-protection agency “they want to pass.” Here’s the thing the South Carolinian may have missed: the agency already passed. It’s part of a little something called “existing federal law.” The Consumer Financial Protection Bureau was signed into law in 2010, after passing the Senate with bipartisan support as part of the larger Wall Street reform package.

Graham isn’t quite sharp enough to even understand the basics of the argument. He insisted yesterday Republicans “don’t want to vote for it.” But no one is asking them to. “It” already exists, whether the GOP likes it or not. It’s now the Senate’s job to consider nominations for the board’s leadership.

Which leads us to the larger problem: what Republicans are embracing in this case is, in effect, nullification.

Congress passed a bill that was signed into law by the president. Last week, a Senate minority — not a majority, a minority — decided it simply won’t allow that law that’s already on the books to be executed.

In case this isn’t obvious, the American system of government isn’t supposed to work this way. Indeed, it’s pretty much the antithesis of our constitutional process.

Republicans may not care about this, but you should.

The GOP minority isn’t even questioning Cordray’s qualifications. Rather, Republicans are saying they refuse to allow existing law to function until Democrats meet the GOP’s demands and does Wall Street’s bidding. When the Senate minority is satisfied, they’ll consider allowing the law to function — if they feel like it.

As a matter of legal and institutional principles, Americans haven’t seen tactics like these since the Civil War. It led James Fallows to explain yesterday, “This strategy depends absolutely for its success on its not being called what it is: Constitutional radicalism, or nullification.” Jonathan Cohn made the same point last week, and Thomas Mann referenced a “modern-day form of nullification” in July.

Political tactics and schemes come and go, as politicians and parties win and lose. But what Republicans are doing now does real damage to the American system of government. It is, by any meaningful definition, a serious and important political scandal.