Plenty of presidents have worked to increase presidential power over the years, but the theory of the unitary executive, first proposed under President Reagan, has been expanded since then by every president, Democrat and Republican alike.

 

Each president since 1980 has used the theory to seize more and more power.

 

The American Bar Assn. denounced this practice in 2006 as presenting "grave harm to the separation of powers doctrine, and the system of checks and balances, that have sustained our democracy for more than two centuries."

Bush's aggressive exercise of unilateral powers has attracted serious opposition. Unfortunately, too many imagine that the unitary executive doctrine and its kingly prerogatives will leave office with him. That hope is false. History teaches that presidents do not give up power -- both Democrats and Republicans have worked to keep it. And besides, hoping the next president will give back some powers means conceding that it is up to him to make that decision.  ( http://www.latimes.com/news/opinion/la-oe-nelson11-2008oct11,0,224216.story )

"The provision of the Constitution giving the war-making power to Congress, was dictated, as I understand it, by the following reasons. Kings had always been involving and impoverishing their people in wars, pretending generally, if not always, that the good of the people was the object. This, our Convention understood to be the most oppressive of all Kingly oppressions; and they resolved to so frame the Constitution that no one man should hold the power of bringing this oppression upon us. But your view destroys the whole matter, and places our President where kings have always stood."   

                                    Abraham Lincoln - 1848