"Truth is truth,†anchor Chuck Todd responded.
"No it isn’t," Giuliani said. "Truth isn’t truth."
Truth of a matter: G is saying someone else's truth is not the same truth another person says is the truth. In other words, interpretation of a matter may vary from person to person.
In Trump's case, a group keeps up with his lies: He lies about 6 times a day. There is no way for him to tell the REAL truth because he does not remember what he says from day to day, and each time to him, what he says is the truth.
They are not going to let him speak to Mueller due to this - they are protecting him from himself. Good for them.