Under the Geneva conventions, yes, but the Rome statute only copies select passages of the Geneva convention, and I don't believe the "we can commit war crimes

Under the Geneva conventions, yes, but the Rome statute only copies select passages of the Geneva convention, and I don't believe the "we can commit war crimes as long as you don't promise not to commit war crimes" is part of what's copied. The Rome Statute does allow foe the ICC to convict according to the Geneva conventions as well, but the exemptions therein don't necessarily apply.