At least according to customary international law, a head of state has full sovereign immunity regardless of any nationalities that they might hold. By the way,

At least according to customary international law, a head of state has full sovereign immunity regardless of any nationalities that they might hold. By the way, the immunity covers not only the head of state, but also the head of government and the Secretary of State. If the Pope were a mere diplomat, his immunities would be restricted to the acts directly related to his job in any country of which he’s a national or permanent resident. That’s because, unlike sovereign immunity, diplomatic immunity is based on a Vienna Convention full of restrictions like that.