Zuckerberg not under oath: exact legal nuances?

According to:

“While Zuckerberg will not be under oath, he will still be required to answer truthfully, as lying to Congress is a federal crime.”

So why not get sworn in? It would look better from a PR standpoint. Are there differences in the penalties for lying, the definition of a lie, the burden of proof for a suspected lie, the followup powers of the questioners, or other things between being sworn in or not?

There are multiple statutes regarding lying to authorities, but as a general matter, an oath isn’t required to have exposure to criminal liability.

But the question is why didn’t they administer an oath? It’s done quite often.

Psychological studies show that if you swear to tell the truth in advance, you are more likely to tell the truth. (200K PDF file)

It’s at the discretion of the chairman running the hearing. I just looked at a handful of transcripts from the Senate Judiciary Committee, one of the two committees involved in yesterday’s hearing, and it doesn’t seem apparent that there is a pattern or policy on which witnesses are sworn in and which are not.

It’s commonly done when witnesses are testifying before the Judiciary Committee. It’s not routinely done when people are testifying before the Commerce Committee.

The presumption here is that this isn’t a criminal investigation and Zuckerberg isn’t a defendant. It’s a hearing on computer security and Zuckerberg is appearing as an expert witness on the subject.

Well, no congressional hearing is ever a criminal investigation, because Congress doesn’t investigate crimes. I think the administration of oaths in congressional testimony seems to be pretty arbitrary.

Suppose Facebook is doing some work for/with US Intelligence services, and a question is asked which the Intelligence services would want answered with a lie. Would not being under oath make it not a crime to lie? That is, is there a loophole that you can lie to Congress in such a case?

James Clapper, the Director of National Intelligence at the time, lied to Congress at a hearing, and cited national security as his rationale when it later came to light that he had done so. There is no recognized exception to the law on that basis, but he was not prosecuted.

There were other explanations, too:

https://www.dni.gov/files/documents/2013-06-21%20DNI%20Ltr%20to%20Sen.%20Feinstein.pdf

Sure it does, but prosecution falls to the Executive Branch:

Remember that the whole thing is basically a public relations show. (It isn’t like they are going to get any evidence that the investigating staff couldn’t have gotten, or maybe already has.)

So the taking/not taking oaths before testimony is just another scene of this show. Included or excluded based on what audience impression it will make. In the 1950’s McCarthy hearings, they included oaths because many of the witnesses were atheists or agnostics, so their taking an affirmation (without “so help me God”) was leave a bad impression on the 1950s public.

In these hearings, they aren’t going to be carried live by network TV, and current audiences are more impatient in their attention, so Congress eliminates boring, time-wasting stuff like administering oaths (that have no legal meaning anyway).

I would be absolutely shocked if staff had interviewed Zuckerberg prior to the hearing, and they knew what he would say at the hearing.

Re PR/Law: I read that (for better or worse considering they gave him special consideration) they cut him a break while “negotiating” his appearance in that the single image of “executive holding palm up in Congress testimony”–that one photo–has become the iconic picture of “crooked corporate titan caught with pants down.”

Where would Contempt of Congress fit into that? Is is not a crime?

Since 1857, yes, but the modern practice is to make a referral to the US Atty. for DC: Contempt of Congress - Wikipedia

Thanks. I was curious because the day Eric Holder was cited for Contempt of Congress (same day as SCOTUS’ Obamacare decision) I was wondering if it was a crime he could be impeached for*.
*Yes an impeachable crime is whatever HoR says it is but let’s assume the accused actually needs to commit a crime.