While people in Eastern Europe can’t vote in this election, Polish Americans, Latvian Americans, Ukrainian Americans and other Americans with roots in countries that feel threatened by an aggressive Russia do. Many of these voters are part of the very demographic groups upon whom Mr. Trump will rely on for his path to victory against Hillary Clinton. Mr. Trump needs a record proportion of white votes to win this election; and he particularly needs them in states of the upper Midwest, including Ohio, Pennsylvania and Wisconsin that have long had large numbers of voters with roots in Eastern Europe.