How is espionage different from the charge ""aiding the enemy""?

They are different in distinct yet similar ways.

Explanation:

Espionage is the practise of using spies or spying to obtain valuable government information which could be military, trade secrets, etc with the aim of helping another country and gaining monetary favours or because of an ideal.

Aiding the enemy is the deliberate or unintentional leaking of government secrets to the enemy or directly helping them by sabotage or other means.

Aiding the enemy charge carries a life imprisonment penalty.

There have been spies in the past that have sold state secrets or defected to another country with state secrets and access codes, this can be considered espionage or treason.

A scenario whereby in war, a citizen of one country helps an enemy soldier by hiding him from soldiers searching for him, that could be considered aiding the enemy.