Poland's nationalistic leadership is refusing to give up a fight against a Polish-American scholar who has claimed that more Jews than Germans were killed by Poles during World War II, a hugely controversial statement in a nation proud of its resistance against the Nazis.

The question is whether Princeton professor Jan Tomasz Gross publicly insulted Poland, a crime punishable by up to three years in prison. A prosecutor recently ordered the continuation of a yearlong investigation until April, overriding a lower-ranking prosecutor who recommended dropping the case after finding no intent to defame Poland.

The case is seen as a test of freedom of speech under a right-wing government that has been centralizing power.