The SCOTUS has made pretty clear that all speech is protected unless it falls into one of these categories:
- Incitement
- Obscenity
- Defamation
- Fraud
- Illegal advertising
- Fighting words
- Threats
- CSAM
"International diplomacy" isn't among the exceptions, and therefore it's protected.
"Interfering with the elected will" is not a crime.
If it were, all protests would be illegal.