Four steps for a successful Trump-Kim summit

President Donald Trump flies to Singapore this week for a potentially legacy-making moment when he meets with North Korean leader Kim Jong-un to discuss a nuclear deal. Based on his tweets, it is clear that Trump is eager to demonstrate to the world that he can make this work and accomplish what his predecessors failed to do. Indeed, he appears more interested in achieving a deal with North Korea than he is in maintaining peace with some of our oldest allies.