As is the case with many legal documents, it's worth paying close attention to the footnotes. In particular, footnote 10 of the Yoo Memorandum contains a tantalizing reference to yet another memorandum, dated October 23, 2001, and summarizes its key conclusion thusly: in the context of the Global War on Terror,
(emphasis in original)
... our Office recently concluded that the Fourth Amendment had no application to domestic military operations.
There are, of course, two questions that flow naturally from Professor Yoo's assertion: (1) how far does this doctrine extend, and (2) has anyone told CAAF?
The March 14, 2003 memorandum can be found online here: [PDF]