This article explores the US-Japan relationship, which is one of the most important strategic partnerships in the world today. It looks at the history of U.S.-Japan relations, outlines specific provisions of the Mutual Defense Treaty between the two countries, and examines how the relationship has evolved. It also examines current status of US-Japan relations, and whether or not the US is committed to defending Japan. The article concludes that Washington remains firmly committed to defending Tokyo should need arise.