Samuel was the last member of the Liberal Party to hold one of the four Great Offices of State (as Home Secretary from 1931–32 in the National Government of Ramsay MacDonald). One of the adherents of "New Liberalism", Samuel helped to draft and present social reform legislation while he was serving as a Liberal cabinet member. Samuel led the party in both the 1931 general election and the 1935 general election, during which period the party's number of seats in Parliament fell from 59 to 21.