http://en.wikipedia.org/wiki/Johnson_v._EisentragerIn their ruling the Supreme Court justices noted (emphasis added and footnotes removed):
…Modern American law has come a long way since the time when outbreak of war made every enemy national an outlaw, subject to both public and private slaughter, cruelty and plunder. But even by the most magnanimous view, our law does not abolish inherent distinctions recognized throughout the civilized world between citizens and aliens, nor between aliens of friendly and of enemy allegiance, nor between resident enemy aliens who have submitted themselves to our laws and non-resident enemy aliens who at all times have remained with, and adhered to, enemy governments. …
But, in extending constitutional protections beyond the citizenry, the Court has been at pains to point out that it was the alien's presence within its territorial jurisdiction that gave the Judiciary power to act. …
If this
Amendment invests enemy aliens in unlawful hostile action against us with immunity from military trial, it puts them in a more protected position than our own soldiers. …
We hold that the Constitution does not confer a right of personal security or an immunity from military trial and punishment upon an alien enemy engaged in the hostile service of a government at war with the United States.
…It is not for us to say whether these prisoners were or were not guilty of a war crime, or whether if we were to retry the case we would agree to the findings of fact or the application of the laws of war made by the Military Commission. The petition shows that these prisoners were formally accused of violating the laws of war and fully informed of particulars of these charges.
See also:
http://www.law.uchicago.edu/tribunals/jve.html
The United States Supreme Court held that the federal Constitution does not confer a right of personal security or immunity from military trial and punishment on alien enemies engaged in the hostile service of a government at war with the United States. The "aliens" concerned were German Nationals who were confined in the custody of the United States Army in Germany following their conviction y a military commission of having engaged in military activity against the United States in China after the surrender of Germany. The Court stated that the military authorities have a jurisdiction, during or following "hostilities" to punish those guilty of offenses against the laws of war, and the German Nationals did not have the right to a writ of habeas corpus.
There's a link to the full opinion on the uchicago page.