STELTER: "The scandals are about the President's lies. About voter fraud, about wiretapping, his repeated lies about those issues. That's the scandal."

CONWAY: "[Donald Trump] doesn't think he's lying about those issues, and you know it."

Holy moly.

Conway's argument goes like this: Donald Trump isn't actually lying because he believes it. In legal circles, this might be referred to as The Costanza Defense.

But, of course, this has nothing to do with whether Trump is telling the truth or not. The truth is determined by its adherence to known facts, not by whether or not you think you are telling it.

Let's break down the two issues Stelter references using that standard definition of "truth."

On voter fraud, Trump has repeatedly insisted that widespread voter fraud in the 2016 election led to 3 to 5 million illegal votes being cast. Those votes for Hillary Clinton are the sole reason she won the popular vote, he argues.

"In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally," Trump tweeted on November 27, 2016 -- 19 days after he won the presidency.

In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally — Donald J. Trump (@realDonaldTrump) November 27, 2016

Not true.

Now on to Trump's allegation that former President Barack Obama ordered a wiretap of Trump Tower during the presidential campaign.

That comes from this tweet sent at 6:35 a.m. ET on March 4 : "Terrible! Just found out that Obama had my 'wires tapped' in Trump Tower just before the victory. Nothing found. This is McCarthyism!"

zero proof for this claim. James Clapper, who was Director of National Intelligence during the 2016 election, said, unequivocally, that it did not happen. "I have no information that supports those tweets," former FBI Director Trump -- and his administration -- offeredproof for this claim. James Clapper, who was Director of National Intelligence during the 2016 election, said, unequivocally, that it did not happen. "I have no information that supports those tweets," former FBI Director James Comey told a congressional committee under oath in May

Put bluntly: Absent proof from Trump -- which has not been forthcoming -- it is safe to conclude that neither widespread voter fraud nor the wire-tapping happened. There is lots of evidence to suggest they didn't. And none -- zero, zilch, zippy -- to suggest they did.

Therefore, what Trump is doing is lying. He may believe it. But that doesn't matter at all.

Think of it this way: I say I won a Pulitzer Prize. The Pulitzer committee has no record of me doing so. When asked to show some proof -- a certificate of some sort, a statuette -- I don't offer it up. But, I am insistent to anyone who asks that, yes, I won one.

It's not unreasonable to conclude in that situation that I am lying about winning a Pulitzer Prize. I can believe that I did and think I am telling the truth. That doesn't change the fact that what I am saying is provably false.

Kellyanne Conway knows that. Which makes her attempt to explain away lies the President keeps repeating all the more ridiculous.