It is not possible to argue that had Jesus been a sinner---because that is an oxymoron.  

Sir, what is the penalty for sin? Death.  Case closed.  That is why Jesus had to die.  He who knew no sin was made to be sin.  Because Jesus took on our sin, he had to pay the price of sin; Death. 
 The wages of sin is death.  That is God the Father's "rule" if you will.  No one can sin and live.

What was that about God and the death penalty again?  His own Son assumed the death penalty so that he could pay the price for sin. Typical liberal that you are---you think God just ignores sin and that there are no consequences for sin.