We have to deter spying with a punishment so severe that nobody in their right mind would consider it. It has to ruin your life forever if you’re caught.
Treating it like stealing a car is ridiculous.
That should be the case for all crimes, but unfortunately there are people out there who would still do them, everything up to and including first degree murder.
Still, for the criminal justice system to be be just, there must be a principle of proportionality: the more severe the crime, the more severe the penalty - and vise versa.
From reading the US espionage statutes in detail, I come away with the impression that the law doesn't distinguish between various levels of espionage and their consequences very well, and so there are some defendants who may be get overly harsh or overly lenient sentences.
But I do know that at the time of the Pollard case, sentences for espionage for a first-time offender working for an ally usually were in the three to five year range. So I don't see my concept of an appropriate penalty in such circumstances to be radical or outrageous.
I agree that the spies within the CIA and FBI should’ve been executed for their betrayal.