The Collaborative International Dictionary of English v.0.48:

Crusade \Cru*sade"\, v. i. [imp. & p. p. Crusaded; p. pr. &
   vb. n. Crusading.]
   To engage in a crusade; to attack in a zealous or hot-headed
   manner. "Cease crusading against sense." --M. Green.
   [1913 Webster]