Certain funding bills sent to GWB by Congress have been vetoed because they require that troops be brought back according to a timetable specified in the bill. Example: HR1591 http://www.cfr.org/content/publications/attachments/1591S.pdf Congress has no constitutional authority to give operational orders to the CinC. If Congress overrides a veto and enacts a law that requires the CinC to, say, re-deploy troops from Iraq – how is that law constitutional? If the CinC signs it, that's the CinC agreeing to give the orders. If he doesn't, then congress is exercising a power it doesnt have.