An election was held in Iran, and a winner was announced by the election authorities.
A loser challenged the results, saying that the election was "rigged" and that he should have won the election.
If anybody claims that an election was fraudulent, then the burden of proof that his claims are true lies on him. Until, and unless, it is proved that an election is fraudulent, the election remains lawful and valid.
In this case the loser has not produced a single concrete allegation of an instance of an election fraud supported by evidence. Instead, the loser launched a public campaign claiming that "everybody knows" that the election was "rigged" and that he is the winner.
This public campaign has lead to a series of violent protests in which public disorder was caused and buses were set on fire. These instances of mass violence received wide coverage and encouragement by foreign media hostile to the present Iranian Government. Some heads of state hostile to Iran made statements in support of this mass violence.
Here again we see another example of violence and lawlessness incited by political demagogy: unsubstantiated claims and allegations aimed at putting politicians into positions of power, or effecting a "regime change" by propaganda (spin).
The liability for any deaths or damage to person and property as a result of political violence, be it wars or civil disorders, within or between states, lies with those who perpetrate it, incite, and encourage it. Governments have right and duty to prevent political violence and punish its perpetrators. If political violence has been perpetrated by governments (e.g. lawless wars, or unjustified violence against individuals), non-government groups have right to use violence to achieve justice only in those cases where justice cannot be achieved by non-violent means.
All disputes should be resolved on the basis of justice, and claims should be supported by evidence and proved by logical reasoning from prime principles. It is the duty of all governments to establish and maintain such legal systems and work for establishment of such systems for resolution of supra-national disputes.