Magna Legis is the most important law in the Constitutio that establishes no bender can turn against a brother or sister with their element power. It was the only law to be ever voted unanimously.
The disobedience to the regiment is considered high treason. The punishment to noncompliance goes as far as death.
After the Grey War some modifications were considered.
This law endured several adaptations throughout history
It currently reads:
"Under penalty of death it is now established that to no bender is permitted to use their conceived element powers against their brothers and sisters in an act of war."