She came into conflict with Chough in the succeeding months in the crisis over the impeachment of President Roh Moo-hyun, with Choo urging Chough to step down over the events. After originally rejecting the role, she was appointed head of the party's election campaign committee less than three weeks before the 2004 parliamentary election. Her fight against regionalism in the party and her management of the party's campaign for the 2004 election during the impeachment crisis earned her the nickname "Choo d'Arc", comparing her to Joan of Arc. She lost her seat in the election. After her re-election to the Assembly in 2008, Choo stood again for the leadership of the United Democratic Party at the party convention on 6 July 2008. She pushed to broaden and deregionalize the party, and enjoyed broad public support, but ultimately placed second behind Chung Sye-kyun. Choo has served as a member of the Assembly's Foreign Affairs and Unification Committee, and in 2003, she was appointed special envoy to the United States on the North Korean nuclear crisis. Choo visited the United Kingdom in November 2010, giving lectures at Chatham House and the University of Cambridge on future policy in the Korean Peninsula. Choo has been accused of using her political influence to exempt her son from mandatory military service. Her son served as a KATUSA, which is widely seen as one of the most prized military posts, for being a relatively comfortable way to serve. Choo has been criticized for her controversial step of not fully disclosing indictments against President Moon Jae-In's allies, of which she is one. Prosecutors have also criticized her broader proposed restructuring of prosecutors' offices.