What is one specific rule or regulation established in international law regarding diplomatic immunity?

Question

What is one specific rule or regulation established in international law regarding diplomatic immunity?

Answer 1

There's an international treaty, negotiated in Geneva, that predates the United Nations.  It established the rules regarding the treatment of diplomats.

Answer 2

A state is not subject to the laws of another state.  Thus, a diplomat in another country cannot be sued thereat due to the principle of diplomatic immunity.

Answer 3

Diplomatic privileges and immunities guarantee that diplomatic agents and/or members of their immediate family:

May not be arrested or detained; may not have their residences entered and searched; may not be subpoenaed as witnesses; and may not be prosecuted.