It's Congress, not a king's court
Second-guess the president? Actually, yes.
The central feature of American government, the one that made the United States "exceptional" and preserved our freedoms for more than 200 years, is in the process of being destroyed. The enemy is not in Iraq or the hills of Pakistan but in Washington and in cities and towns throughout the United States.
America's Founders, it turns out, were not as smart as we thought. They assumed that if they put most of the nation's real powers – over war, taxes, and spending – in the hands of the people themselves, through their representatives, those representatives would do their duty and prevent an American president from acting as though he were king.
Congress was not to be a copy of the British Parliament but its exact opposite: Whereas Parliament is essentially an extension of the executive (the prime minister's party always controls Parliament and its members are expected to enact his or her proposals) and members need not have any connection to the "constituencies" they allegedly represent, the American system requires members of Congress to come from the states they represent and to serve as a check on – not enabler of – the president.
It's a simple enough concept, but one apparently hard for members of Congress to grasp.