Attorney General Holder has sent this letter to Senators Reid and McConnell, objecting to the GTMO-transfer restrictions in the pending Continuing Resolution bill as an "extreme and risky encroachment on the authority of the Executive branch to determine when and where to prosecute terrorist suspects." As Josh Gerstein observes, however, there is no word yet of an actual veto threat.
One notable feature of the letter is that it does not mention military as opposed to prosecutorial equities and authorities. Of course, the letter is from the Attorney General, not the Secretary of Defense. But will there will be a comparable DOD letter, or some other statement suggesting that the legislative encroachment here has to do with more than prosecutorial interests, given that we are speaking of military detainees? That is, will anyone invoke anything smacking of the Commander-in-Chief authority? Certainly that would cause some agitation on the left, though in this case invocation of commander-in-chief authority would be directed toward an end that the left largely favors (i.e., GTMO closure and domestic prosecutions as an option).