A woman passes by posters that express Polish opposition to Russia, in Warsaw, Poland. The posters imply a comparison of Russia today with Adolf Hitler’s Germany. They say “Achtung Russia,” German for “Beware of Russia,” with a reference to the SS, a brutal Nazi unit. President Barack Obama’s visit to Warsaw last month brought a wave of relief in Poland. Fears were running high over Russian aggression in Ukraine, and Obama’s pledge of security protections for his NATO partner was just the message the Poles were craving.