They controlled chairmanships of numerous important committees, which were established by seniority. He also held key chairmanships for the agriculture and highway committees. Committee memberships, including chairmanships and vice chairmanships, are assigned by the Speaker. He lost his chairmanships in 2007 when the Democrats regained control of the Senate. She was given committee chairmanships, among many other roles. The 1940s started an era of key committee chairmanships for Hayden. Hayward had several other important Chairmanships from 1937. His four chairmanships have not been matched.