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President Arends is the leader of the Nationalist party on planet Terra who vies for peace with the fascist Eastern Alliance that propagated the Lunar Colonies. Extremely over-zealous and paranoid in how he conducts efforts of hammering out a peace treaty beneficial for sides, Arends has both military and government supporters suppress information from the general population and other members of the government -- such as Paradeen's destruction by Alliance hands and the takeover the Lunar Colonies.
When his assistant, Moore, informs him of the return of Charlie Watts (Apollo, actually) and the two unidentified blips (Vipers), Arends orders Brace and his men to apprehend anyone who has been in contact with him or has knowledge about Watts' return. He also stresses the importance of the peace treaty and doesn't trust the Nationalist Precedium for they were, in his words, "war mongrels".
Later having been freed by Starbuck, General Maxwell and Apollo attempt to convince the Precedium of Arends' actions and that they must maintain peace. Maxwell manages to convince Arends that the Alliance would do anything for total domination.
Unfortunately, in order to enforce the peace treaty, Galactica has to intercept all the nuclear missiles coming to and from Terra. Arends begins to realize the error in his ways and, along with Maxwell, attempts to gain military and technological secrets from Apollo, who disappears at John's whim (Experiment in Terra).