Examples of heads of state in parliamentary systems using greater powers than usual, either because of ambiguous constitutions or unprecedented national emergencies, include the decision by King Leopold III of the Belgians to surrender on behalf of his state to the invading German army in 1940, against the will of his government. Judging that his responsibility to the nation by virtue of his coronation oath required him to act, he believed that his government's decision to fight rather than surrender was mistaken and would damage Belgium. (Leopold's decision proved highly controversial. After World War II, Belgium voted in a referendum to allow him to resume his monarchical powers and duties, but because of the ongoing controversy he ultimately abdicated.) The Belgian constitutional crisis in 1990, when the head of state refused to sign into law a bill permitting abortion, was resolved by the cabinet assuming the power to promulgate the law while he was treated as "unable to reign" for twenty-four hours.