That is exactly what ICC and ICJ should do in an joint Action to show, International law still exist and should not be denied or breached in systemic disrespect of it. It should show that it will reach violators and enforce justice even if there are multiple nationals involved in something like conspiracy to commit…
or Aiding and abetting to commit…
When those political figures willingly act against International law and humanitarian law, UN-Charter, ICJ rules etc.
It must keep up with the challenge of those who commit violations and breaches of law in systemic actions.
Otherwise it would show there is no international law, just empty words and wishful thinking of those laws.