The classical definition of national interest says that foreign policy must defend the state against threats to its power.
Power is taken as an end in itself.
If you win, I lose. Concessions are seen as national humiliations. The China-U.S. standoff over the downed American intelligence aircraft was treated in this way in much of the press, and in the Washington political debate. Conservatives in both Washington and Beijing insisted that compromise would produce a humiliating loss of national prestige. This reflects a classical conception of power and state relations, as old as the European dynastic state.