When President-elect Joe Biden walks into the White House on January 20, 2021, a wide range of pressing foreign-policy challenges will await him. Arguably, none is more urgent than North Korea. In the first hundred days of his administration, President Biden should declare the 70-year Korean War over and appoint a special envoy to negotiate a peace treaty, with an eye toward reconciliation with North Korea and gradual denuclearization of the Korean Peninsula.