Politics in a central European country of just 10 million people might not seem consequential. But that’s not the case in Austria, where there’s a good chance its election Sunday will be won by a far-right, pro-Russia party that was founded by former Nazis.

A win for the Freedom Party, or FPÖ, would not just have historical connotations — Austria was the birthplace of Adolf Hitler — it could tilt the balance of power between Russia and the West.

Though small, Austria has for centuries…