First, almost any contract would include a force majeure clause which allows termination due to a war (among other acts). Failing that, the German government c

First, almost any contract would include a force majeure clause which allows termination due to a war (among other acts). Failing that, the German government could just change the law to disallow the contract. Russia could ask for a binding(ish) decision from the international community, but this is one of those situations where I doubt the decision would go in their favor even if they were in the right legally.