How severely would you punish espionage, stealing our national secrets, and giving them to a country we’re not at war with?
A stern letter? Something in your permanent record?
Barring very unusual circumstances, a prison term in the range of three to five years.
Espionage of national security secrets is still a crime against the state but it is neither treason (aid and comfort to the enemy in a time of war) nor sedition (efforts to overthrow our form of government).
The standard has been 2 to 5 years. Pollard is way over and nobody else has been close.