Part of the The International Criminal Court Unpacked series

The International Criminal Court (ICC) is governed by the Rome Statute to which, neither Ukraine nor Russia are party to. Accordingly, the ICC would have no jurisdiction to investigate crimes in the current conflict. However, the court relies on article 12(3) outlining the preconditions to the exercise of jurisdiction: 

If the acceptance of a State which is not a Party to this Statute is required under paragraph 2, that State may, by declaration lodged with the Registrar, accept the exercise of jurisdiction by the Court with respect to the crime in question. The accepting State shall cooperate with the Court without any delay or exception in accordance with Part 9.

The court is able to rely on this article as the Ukrainian government had lodged two declarations, November 2013 - February 2014 and February 2014 onwards, accepting the ICC jurisdiction in respect to alleged crimes committed on Ukrainian Territory. 

As the conflict developed and international concern increased, referrals from 44 states party to the statute further legitimised the exercise of ICC jurisdiction in Ukraine. This is pursuant to article 13(a)

The Court may exercise its jurisdiction with respect to a crime referred to in article 5 in accordance with the provisions of this Statute if:

1. A situation in which one or more of such crimes appears to have been committed is referred to the Prosecutor by a State Party in accordance with article 14; 

The ICC has legitimate authority in investigating war crimes in Ukraine. The authority is derived from the Rome Statute that governs the court. The outcome of the investigation will be a paramount in settling the debates surrounding the court in recent years.