In the passage, the author is primarily concerned with A. showing how the Vietnam conflict led to a new interpretation of the Constitution's provisions for use of the military B. arguing that the War Powers Resolution of 1973 is an attempt to reclaim a share of constitutionally concurrent power that had been usurped by the President C. outlining the history of the struggle between the President and Congress for control of the military D. providing examples of conflicts inherent in the Constitution's approach to a balance of powers E. explaining how the War Powers Resolution of 1973 alters the Constitution to eliminate an overlap of authority