A really good article in The New York Times Sunday Magazine by Noah Feldman titled: Our Presidential Era: Who Can Check the President? about the expanding powers of the President. It begins with:

Not since Watergate has the question of presidential power been as salient as it is today. The recent revelation that President George W. Bush ordered secret wiretaps in the United States without judicial approval has set off the latest round of arguments over what the president can and cannot do in the name of his office. Over the past few years, the war on terror has led to the use of executive orders to authorize renditions and the detention of enemy combatants without trial - for which the Bush administration has been called to account by our European allies. The treatment of detainees has also given rise to concerns in Congress about the prerogatives of the chief executive: both houses recently voted to limit the president's authority to employ C.I.A. or other executive agents to engage in cruel and inhumane interrogations. The limits of presidential power will almost surely be a major topic of discussion during Samuel A. Alito Jr.'s Supreme Court confirmation hearings, which are scheduled to begin this week.

The stakes of the debate could hardly be higher: nothing is more basic to the operation of a constitutional government than the way it allocates power. Yet in an important sense, the debate is already long over. By historical standards, even the Bush administration's critics subscribe to the idea of a pre-eminent president. Administrative agencies at the president's command are widely understood to be responsible for everything from disaster relief to drug approval to imposing clean-air standards; and the president can unleash shock and awe on his own initiative. Such "presidentialism" seems completely normal to most Americans, since it is the only arrangement most of us have ever known.

For better or worse, though, this is not the system envisioned by the framers of the Constitution. The framers meant for the legislative branch to be the most important actor in the federal government: Congress was to make the laws and the president was empowered only to execute them. The very essence of a republic was that it would be governed through a deliberative legislature, composed carefully to reflect both popular will and elite limits on that will. The framers would no sooner have been governed by a democratically elected president than by a king who got his job through royal succession.