If you hang around in Republican circles, it won’t take long before you hear the term “constitutional conservative.”

Republicans like to hold themselves up as the torchbearers for America’s founding principles. They fancy themselves true patriots, in contrast with those rascally Democrats who “hate America.”

But as much as they talk about the Constitution, a lot of these Republican politicians don’t really know a whole lot about it.

The recent brouhaha centering on Ben Carson illustrates this point. During a C-SPAN interview, the Republican presidential contender responded to a question about which founding father impressed him the most.

I’m impressed by a lot of them, but particularly impressed with Thomas Jefferson, who seemed to have very deep insight into the way that people would react,” Carson said. “And he tried to craft our Constitution in a way that it would control people’s natural tendencies and control the natural growth of the government.”

Of course, Thomas Jefferson was in France during the Philadelphia Convention and had no input into “crafting” the Constitution whatsoever.

Let’s be honest. If you do many live interviews at all, you will make some mistakes. Your mind freezes up. You misspeak. You answer a simple question with incoherent garble.

It happens.

But instead of just allowing a little mistake to be a mistake, Carson supporters immediately jumped to his defense, proving their own ignorance of the Constitution.

Apparently, USA Today deputy editorial page editor David Mastio used Google and discovered Jefferson wrote some letters to James Madison and George Washington during the Philadelphia Convention, and the Jefferson continued correspondence during the ratification debates, expressing his views on the proposed government.

Based on the existence of these letters, Mastio concluded with maximum snark, “I guess he [Carson] sorta did know what he was talking about, after all.”

Except he didn’t.

And Mastio doubled down on Constitutional ignorance asserting Jefferson “had this other idea called a ‘Bill of Rights,’ which you might have heard is a part of the Constitution.

Jefferson certainly supported a Bill of Rights, and he expressed this in his correspondence with Madison. But it was in no way shape of form “his idea,” despite the assertion of some dude from the ACLU Mastio quotes.

Nevertheless, sensing blood in the water, conservative talk show host Rush Limbaugh read Mastio’s op-ed on the air and triumphantly claimed Carson was vindicated. America’s favorite conservative talking head loves to blather on about the Constitution, but he clearly doesn’t know much about it either.

Historian Kevin Gutzman counts among America’s leading experts on colonial and post-revolutionary America. He wrote an acclaimed biography of James Madison and is currently working on a Jefferson biography. In other words, Dr. Gutzman’s know what he’s talking about. He took these fallacious notions about Jefferson’s influence on the Constitution head-on.

Not only is it not ‘obviously’ true that Thomas Jefferson’s ideas were ‘crucial to the final documents,’ there is NO EVIDENCE AT ALL THAT HE HAD ANY EFFECT ON THE CONSTITUTION. NONE. ZERO.

1) He was in France in summer 1787, at a time when it took five weeks for a letter to cross the Atlantic to the east and longer to the west. The delegates to the Convention were all sworn to secrecy, so they could not have consulted him even if they had desired to do so and it had been practicable.

2) The first promise to seek a bill of rights was made by Federalists in Massachusetts to get Governor John Hancock and other waverers to support ratification. None of them consulted Jefferson–who was still in France, if anyone in Boston had cared. James Madison was finally persuaded to favor a bill of rights, which he had opposed, by political imperatives in Virginia: the North American Baptist movement happened to be centered in his home county, and local Baptists insisted he promise to seek amendments, particularly one like the Establishment Clause, before they voted for him over James Monroe for Congress. Everyone knew this was his motivation at the time.

There is no Jefferson scholar on earth who will join in saying that Jefferson crafted the Constitution. None. Nor can you name one idea of his that is in the Constitution.

So, why does any of this really matter?

Because these people claim to champion the Constitution. If they get the basic history so wrong, how in the world can we count on them to actually get what it means right? More importantly, how can we expect them to follow it?

Of course, they don’t.

“Constitutional conservatives” frequently support violations of the Constitution they claim to revere with undeclared wars, federal spy programs, the “war on drugs,” “common-sense” gun control, federal meddling in health care, federal meddling in education…the list goes on and on. Carson himself said he would “intensify” the drug war.

The moral of the story – don’t let the talk fool you. Don’t support these guys just because they name-drop your favorite founding father and talk about “constitutional principles.”

These politicians don’t care about the Constitution. They don’t even know anything about it. And they’ve reduce America’s founding document to a campaign slogan.