[shiciapsisy]

The Congress shall have power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States; but all duties, imposts and excises shall be uniform throughout the United States [...]

To make rules for the government and regulation of the land and naval forces; The rule in question here is redeployment (incidentally, the House bill is binding). So yes, this does pass Constitutional muster. There's plent of precedent to back up the general idea (Little v. Barreme, Youngstown v. Sawyer, Hamdan, etc.).

That said, a court decision could go easily against Congress, and defunding (as mandated by the recently introduced Feingold-Reid legislation) doesn't need to get past a veto.