It is a tired, but apropos, joke: how do you know when a politician is lying? When his/her lips move.

Tuesday, Susan Rice was flapping her lips like a loose sail in a stiff breeze. She should have known better. Whenever she talks, trouble is sure to follow. For her.

Rice chose a benign venue in appearing on "Andrea Mitchell Reports" on MSNBC, but even that didn’t help.

The story she peddled was blatantly self-serving and punctuated with a glaring contradiction.

All of which invites the question, did she break the law in the waning days of the Obama administration when she served as National Security Adviser?

Rice denied leaking intelligence information about President Trump’s associates, yet she defended her requests to unmask the identities of U.S. citizens caught up in surveillance operations.

Here is how the law applies to Rice’s conduct. Or at least her version of it.

Unmasking Names

Rice acknowledged in the interview with Mitchell that she requested that names be unmasked, but she insists she did not do it for political purposes. It is an important distinction.

Under the U.S. Signals Intelligence Directive (section 18), Rice was authorized to unmask the names of U.S. citizens, as long as it was essential to national security. Sure enough, Rice claims that national security was her reason.

Here is the rub. It would be difficult for a prosecutor to prove otherwise. Likely, only Rice knows her true intent, and it is doubtful she authored a smoking-gun memo that reads, “let’s unmask these names so we can use their identities for political gain.”

But if such an email exists or if someone were to come forward to allege that Rice verbally confided her motivation was for political reasons, then she would be looking at a serious felony punishable by up to 5 years behind bars.

Rice could face an additional problem. If she requested that a name be unmasked in a document that had nothing whatsoever to do with foreign surveillance involving national security, an argument could be made that she created a false statement in her unmasking request, which is a crime under 18 USC 1001.

Leaking Names

Whoever leaked Michael Flynn’s name or any other names collected incidentally during surveillance, committed multiple crimes because those names are classified information.

Under 18 USC 798, it is a felony to knowingly and willfully communicate classified material to an unauthorized person.

A similar law, 50 USC 1809, forbids the unauthorized disclosure of national security information. Three other statutes may also have been violated.

The Washington Post reporter who received Flynn’s name described his source in a January 12, 2017 column as “a senior U.S. government official.” That would be a description of many people in Washington, Rice included. But she was in a unique position to have had access to what was supposed to be classified material.

Nevertheless, Rice insists she did not leak any names. Absent some proof that she is lying, she cannot be prosecuted. However, there is ample reason for people to suspect Rice is not telling the truth.

Rice’s Changing Story

In the course of less than 2 weeks, the story Rice has told seems to have changed significantly.

On March 22, she was asked by Judy Woodruff on PBS' "NewsHour” if she knew whether “Trump transition officials, including the president, may have been swept up in surveillance of foreigners at the end of the Obama administration”. In other words, incidental collection.

Rice responded, “I know nothing about this.”

Yet Tuesday she reversed herself completely, claiming she knew all about it. That is, she knew of the incidental collection and, further, she is the one who requested that names be unmasked. Yes, she spoke in generalities, but is there any doubt she was referring to Trump associates?

It is an understatement to say that Susan Rice lacks credibility. And this would not be the first time she conjured up a false narrative.

She infamously hustled the deception that a videotape triggered the Benghazi attack in September 2012. Later, when incriminating emails surfaced, she admitted the story was untrue.

She further tarnished her reputation when she said that Army Sgt. Bowe Bergdahl, who faces charges of desertion and consorting with the enemy, served with “honor and distinction.”

Susan Rice has an abysmal track record of telling the truth. Her remarks Tuesday about the unmasking of surveillance may be another example.

Never Leaked Anything?

Rice seems to have taken her denials one step too far. During her MSNBC interview she declared, “I leaked nothing to nobody, and never have.” Really?

That’s next to impossible. Is there a person in Washington who hasn’t leaked something at some time to someone? If you can find that person, we should throw a parade.

So, when Rice makes a ludicrous statement like that, there is even more reason to doubt her veracity.

When asked if she would testify before Congress, Rice refused to answer. I hope she has good counsel. She would be testifying under oath. It is a serious crime to lie to Congress.

My guess is she’ll do everything she can to avoid raising her right hand.