If President Obama really does welcome a debate about the scope of the U.S. surveillance program, a good first step would be to fire Director of National Intelligence James Clapper.

Back at an open congressional hearing on March 12, Sen. Ron Wyden (D-Ore.) asked Clapper, “Does the NSA collect any type of data at all on millions or hundreds of millions of Americans?” Clapper replied, “No sir … not wittingly.” As we all now know, he was lying.

We also now know that Clapper knew he was lying. In an interview with NBC’s Andrea Mitchell that aired this past Sunday, Clapper was asked why he answered Wyden the way he did. He replied:

“I thought, though in retrospect, I was asked [a] ‘when are you going to … stop beating your wife’ kind of question, which is … not answerable necessarily by a simple yes or no. So I responded in what I thought was the most truthful, or least untruthful, manner by saying, ‘No.’ ”

Let’s parse this passage. As a member of the Senate Intelligence Committee, Wyden had been briefed on the top-secret-plus programs that we now all know about. That is, he knew that he was putting Clapper in a box; He knew that the true answer to his question was “Yes,” but he also knew that Clapper would have a hard time saying so without making headlines.

But the question was straightforward. It could be answered “yes” or “no,” and Clapper had to know this when he sat there in the witness chair. (Notice that, in his response to Mitchell, Clapper said he came up with the wife-beating analogy only “in retrospect.”) There are many ways that he could have finessed the question, as administration witnesses have done in such settings for decades, but Clapper chose simply to lie. “Truthful” and “untruthful” are not relative terms; a statement either is or isn’t; there’s no such thing as speaking in a “most truthful” or “least untruthful” manner.

Nor was this a spontaneous lie or a lie he regretted making. Wyden revealed in a statement today that he’d given Clapper advance notice that he would ask the question and that, after the hearing, he offered Clapper a chance to revise his answer. Clapper didn’t take the offer.

Clapper’s deceptions don’t stop there. Rambling on in his rationalization to Mitchell, he focused on Wyden’s use of the word “collect,” as in “Did the NSA collect any type of data … on millions of Americans?” Clapper told Mitchell that he envisioned a vast library of books containing vast amounts of data on every American. “To me,” he said, “collection of U.S. persons’ data would mean taking the book off the shelf and opening it up and reading it.”

If this were true, it would suggest that Clapper wasn’t quite lying when he told Wyden that the NSA doesn’t wittingly “collect” data on Americans. But of course, this is nonsense. Neither in everyday speech nor in tech-intelligence jargon does “collect” mean anything other than what it obviously means: to gather, to sweep up, to bring together. No one says, “I’m going to collect The Great Gatsby from my bookshelf and read it.” Nor does anyone say, “I’m going to collect this phone conversation from my archive and listen to it.”

It is irrelevant whether Clapper really believes his definition of “collect” or made it up on the spot. Either way, this is a man who cannot be trusted to hold an honest discussion about these issues. If he lied about what he thinks “collect” means, he will lie about lots of things. If he really thinks the English language is this flexible, it is unwise to assume that any statement he makes means what it appears to mean.

This is crucial. We as a nation are being asked to let the National Security Agency continue doing the intrusive things it’s been doing on the premise that congressional oversight will rein in abuses. But it’s hard to have meaningful oversight when an official in charge of the program lies so blatantly in one of the rare open hearings on the subject. (Wyden, who had been briefed on the program, knew that Clapper was lying, but he couldn’t say so without violating the terms of his own security clearance.)

And so, again, if President Obama really welcomes an open debate on this subject, James Clapper has disqualified himself from participation in it. He has to go.