The Washington Post’s report that Attorney General Jeff Sessions spoke twice with Russian Ambassador Sergei Kislyak during the 2016 presidential campaign has made an exchange between Minnesota Democratic Senator Al Franken and Sessions during his confirmation hearing the focus of questions about whether Sessions misled Congress.

On January 10, in response to a question from Franken, Sessions said that he had no communications with the Russian government. Here is the exchange:

FRANKEN: OK. CNN has just published a story and I'm telling you this about a news story that's just been published. I'm not expecting you to know whether or not it's true or not. But CNN just published a story alleging that the intelligence community provided documents to the president-elect last week that included information that quote, "Russian operatives claimed to have compromising personal and financial information about Mr. Trump." These documents also allegedly say quote, "There was a continuing exchange of information during the campaign between Trump's surrogates and intermediaries for the Russian government."

Now, again, I'm telling you this as it's coming out, so you know. But if it's true, it's obviously extremely serious and if there is any evidence that anyone affiliated with the Trump campaign communicated with the Russian government in the course of this campaign, what will you do?

SESSIONS: Senator Franken, I'm not aware of any of those activities. I have been called a surrogate at a time or two in that campaign and I didn't have––did not have communications with the Russians, and I'm unable to comment on it.

Justice Department officials told the Post that “Sessions met with Kislyak on Sept. 8 in his capacity as a member of the armed services panel rather than in his role as a Trump campaign surrogate.” After the Post story broke Wednesday night, Sessions spokesperson Sarah Isgur Flores released a statement from Sessions saying, “I never met with any Russian officials to discuss issues of the campaign. I have no idea what this allegation is about. It is false.”

Set aside for a moment the contradiction between Sessions having “no idea” what the allegation is about, but also knowing that it is false. The follow-up statement contains a qualification Sessions’s original testimony did not explicitly include. It says Sessions never met with Russian officials “to discuss issues of the campaign.” It does not say that Sessions did not recall his encounters with Kislyak, or that he did not meet with him, only that he did not discuss campaign issues with him.

Had Sessions’s response to Franken contained the same qualifications as his statement Wednesday night, the next questions would have been about the circumstances in which Sessions met with Russian officials, and the content of those discussions. If he had said that he had met with the Russian ambassador as a senator but not as a campaign surrogate, or that he met with the Russian ambassador but did not discuss campaign issues with him, it would have provoked further controversy regarding a negative story the Trump administration was desperate to tamp down: The extent of the Trump campaign’s contacts with the Russian government. Sessions’s blanket denial put an end to that line of questioning––a denial that was freely offered by Sessions himself, not directly in response to Franken’s query.

There’s no evidence that Sessions’s communications with Kislyak were anything but benign. Neither is there any indication that Sessions knew anything about what American intelligence agencies have said was a deliberate effort to swing the election to Trump by hacking and disclosing embarrassing information about Democrats. But there is also no question that by January, his contact with Kislyak had become a politically inconvenient fact to publicly acknowledge.

Flores has said that he “met with the ambassador in an official capacity as a member of the Senate Armed Services Committee, which is entirely consistent with his testimony.” But his answer to Franken offered no such explicit qualification. On the other hand, perjury is notoriously hard to prove, because it requires the subject to have knowingly misled Congress, not to have answered incorrectly as a matter of confusion, misunderstanding, or error. Sessions claims that he was speaking only about contacts he might have had as a Trump surrogate; omitting to mention other contacts likely wouldn't qualify as perjury under the law, even if it amounts to misleading the Senate about his actions.

Had Sessions qualified his statement at the time in the same manner that he has since the Post story appeared, by saying that he did not have communications with the Russians “as a Trump campaign surrogate,” the same questions being asked now would have been raised then. But by not disclosing the contacts in January and answering those questions in his hearing, he has shifted the focus from the nature of the conversations themselves, to questions about his honesty and ability to administer justice impartially.

Even before the latest disclosures, two dozen nonprofits, as well as all the Democrats on the Senate Judiciary Committee, had called on Sessions to recuse himself, arguing that his role as a key Trump campaign adviser required that step under a plain reading of Justice Department guidelines. That was before Sessions’s communications with Kislyak were publicly known, but Sessions himself already knew of them and still did not recuse himself.

"I have said whenever it's appropriate, I will recuse myself," Sessions told NBC News on Thursday morning. "There's no doubt about that." But he stopped short of actually doing so.

Republican members of Congress, including House Oversight Chairman Jason Chaffetz and Representative Justin Amash, are already calling for Sessions to recuse himself from the ongoing federal investigation into the Trump campaign’s contacts with the Russian government in light of these revelations.

If Sessions does ultimately recuse himself, though, it will only be because he withheld pertinent information that has now become public knowledge. That’s a remarkable standard for the top law-enforcement official in the country to set.