Mora v. McNamara (p. 369)

 The Supreme Court denied cert concerning whether draftees could be sent to fight in the Vietnam conflict. The issue was whether a war had been declared by Congress, and if not, whether "the Executive constitutionally [may] order the petitioners to participate in that military activity." casebook p. 369

By refusing to take the case, the Court basically allowed the political branches--Congress and the Executive--to determine the resolution of these issues. Congress had (sort of) authorized the President to take military action in the Gulf of Tonkin Resolution.

Once we are involved in a military conflict, the issue probably becomes a political question to be resolved by the President as Commander in Chief and Congress through the power of the purse. Not by the Court in litigation brought by draftees who wish not to participate.