The U.S. military has been wary of cooperating with the Hague court because of concerns it might try to prosecute U.S. troops in the future.
The Defense Department is blocking efforts by the U.S. government to share evidence of possible Russian war crimes in Ukraine with the International Criminal Court, a senior U.S. diplomat told lawmakers Wednesday.
Beth Van Schaack, the State Department’s ambassador-at-large for global criminal justice, said at a hearing of the Senate Foreign Relations Committee that the Pentagon continues to hold up U.S. cooperation with the Hague court in its investigations of suspected atrocities in Ukraine. 
When Sen. Chris Van Hollen, D-Md., asked Van Schaack whether it was the Pentagon that “is not cooperating in that way,” she replied: “Yes.”
The Pentagon has harbored concerns that cooperation with the International Criminal Court could lead to the prosecution of U.S. troops deployed abroad. The New York Times first reported in March the Pentagon’s reluctance to share information about Ukraine with the ICC. 
The ICC opened an investigation into possible U.S. crimes in Afghanistan in 2017. The Trump administration immediately expressed outrage and imposed sanctions on the court’s prosecutor. Court officials later announced that the case against U.S forces in Afghanistan would receive lower priority.
Van Schaack argued at Wednesday’s hearing that sharing relevant information about suspected war crimes in Ukraine with the Hague court would not raise potential legal risks for U.S. troops. She also pledged to fight any such effort by the court.
“I’ll say at the outset that in my role as the lead diplomat in the international justice space, I would work tirelessly to ensure that no U.S. personnel will be brought before the ICC,” she said. “I do not think that that is an acute risk at this time.” 
The ICC has also assured U.S. officials that if the U.S. legal system addresses possible war crimes committed by American troops, the Hague court would not see a need to intervene, she added.
“I do not think,” she said, “that we are at all undermining our ability to robustly protect against any charges that might be brought.”

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