The red line is when Iran violates international law. Then Israel files the complaint with the ICC and goes to the hearing with the appropriate and sufficient evidence. Iran has to sign additional safeguard addenda noting that it will cooperate with ICC proceedings upon issuance of a valid and verifiable complaint as allowed by international law to Israel. Another red line regarding Iran is that if Israel strikes without our consent, there will be consequences and we bear zero complicity.
Clashes between IDF and protesters in Bethlehem and East Jerusalem (Reuters)