Isolationism is a form of foreign policy that advocates non-interventionism and keeping the affairs of other countries at a distance, in favor of focusing on domestic issues. Isolationism was famously practiced in Asian countries such as Japan and China during the 19th century, and violent xenophobic movements were formed in both countries with the goal of maintaining isolationism, namely the Sonno joi movement in Japan and the Boxers of China. Another notable example was the United States, whose conservative politicians sought to keep out of European affairs and focus on issues in North America. During the 1930s and early 1940s, the issue was prominent due to the start of World War II, with the Taftite Republicans and Conservative Democrats opposing intervention in Europe and the New Deal Democrats and Rockefeller Republicans supporting the USA's entry into the war on the side of the Allied Powers. Ultimately, the Attack on Pearl Harbor on 7 December 1941 led to the public uniting in support of the war, and American isolationism was shattered.