Source : Webster's Revised Unabridged Dictionary (1913)

Constitutionalism \Con`sti*tu"tion*al*ism\, n.
   The theory, principles, or authority of constitutional
   government; attachment or adherence to a constitution or
   constitutional government. --Carlyle.

Source : WordNet®

constitutionalism
     n 1: a constitutional system of government (usually with a
          written constitution)
     2: advocacy of a system of government according to
        constitutional principles