ma·jor·i·tar·i·an 
(mə-jôr′ĭ-târē-ən, -jŏr′-)
(mə-jôr′ĭ-târē-ən, -jŏr′-)adj.
Of, relating to, or advocating majority rule, especially as a political principle: "a naively uncomplicated premise of simple majoritarian democracy" (Saturday Review).
n.
An advocate of majoritarianism.