semiotics Balkin coined the term ideological drift to describe a phenomenon by which ideas and concepts change their political valence as they are introduced into new social and political contexts over time. Along with Duncan Kennedy, Balkin developed the field of legal semiotics. Legal semiotics shows how legal arguments feature recurrent tropes or topoi that respond to each other and whose opposition is reproduced at higher and lower levels of doctrinal detail as legal doctrines evolve. Hence Balkin claimed that legal argument has a self-similar "crystalline" or fractal structure. Balkin employed deconstruction and related literary theories to argue that legal thought was structured in terms of "nested oppositions"—opposed ideas or concepts that turn into each other over time or otherwise depend on each other in novel and unexpected ways. Although he draws on literary theory in his work on legal rhetoric, Balkin and his frequent co-author Sanford Levinson contend law is best analogized not to literature but to the performing arts such as music and drama. Partisan entrenchment Balkin and Levinson argue that constitutional revolutions in judicial doctrine occur through a process called partisan entrenchment. The party that controls the White House can stock the federal courts with new judges and Justices who have views on key constitutional issues roughly similar to those of the President. This shifts the median Justice on the Supreme Court and changes the complexion of the lower federal courts, which, in turn, eventually affects constitutional doctrine. If enough new judges are appointed in a relatively short period of time, changes will occur more quickly, producing a constitutional revolution. For example, a constitutional revolution occurred following the New Deal because Franklin Roosevelt was able to appoint eight new Supreme Court Justices between 1937 and 1941. Balkin and Levinson's theory contrasts with Bruce Ackerman's theory of constitutional moments, which argues that constitutional revolutions occur because of self-conscious acts of democratic mobilization that establish new standards of political legitimacy. Balkin and Levinson view partisan entrenchment as roughly but imperfectly democratic; it guarantees neither legitimate nor correct constitutional interpretation. Constitutional interpretation Balkin's constitutional theory, developed in his 2011 book, Living Originalism, is both originalist and living constitutionalist. He argues that there is no contradiction between these approaches, properly understood. Interpreters must follow the original meaning of the constitutional text but not its original expected application; hence much constitutional interpretation actually involves constitutional construction and state building by all three