Durbin of Illinois, while his Democratic colleague from Michigan, Carl Levin, noted the military's top leadership fully backed the exchange. Whether you agree with them or not, its critically important that the American people know that the chairman of the Joint Chiefs and the vice chair of the Joint Chiefs strongly recommended this agreement knowing full well Bergdahl, one, had left his unit and knowing full well how bad these Taliban people were, Levin said. The dispute involves both the dynamics of the exchange and the endless argument between the executive and legislative branches over presidential powers. Legal requirement or courtesy ? Members of both parties complain the Obama administration should have let Congress know ahead of time that the exchange was taking place. Some cite the 30 daysnotice called for by the National Defense Authorization Act, while others say a simple heads-up would have sufficed. It's just a matter of courtesy, whether it was in law or not, said conservative Sen. Jeff Sessions of Alabama, a regular critic of the President. A matter of this importance should have been discussed with at least key leaders in the Congress. Administration officials say the deal came together quickly, and the risks to Bergdahl and the military commandos involved in collecting him near the Afghanistan-Pakistan border required keeping the exchange top-secret. This