Blasphemy is to religion as treason is to ...

Reason?

Government?

The constitution?

Government.

Explanation:

Treason is a violation or attack against a person's government which puts the safety of the government at risk. Blasphemy is speaking or acting against a person's religion which attacks the belief system of that religion.

The US considers attacks or plots to attack the government and/or rebellion to overthrow the government is considered treason.

Treason is a federal offense which can experience the worst punishment.