People arrive at the border crossing between Poland and Ukraine, after Russia launched a massive military operation against Ukraine, in Medyka, Poland, February 25, 2022. REUTERS/Kacper Pempel The United States is playing a secondary role to European nations as thousands of refugees flee Ukraine, providing emergency aid but signaling that Europe should be their primary destination. As Russia invaded Ukraine this week, the United States dispatched disaster experts to the region to assess the need for humanitarian assistance and urged neighboring countries to keep their borders open to refugees. President Joe Biden’s administration last year launched a mass evacuation of...