Though Obama's power grab is unprecedented, his philosophy is not. It has roots in the progressivism of the early 20th century, when Woodrow Wilson ripped the Constitution as an archaic document that prevented him from crafting social change. He said the president should be a visionary rather than a mere vessel of the people. The president, he said, has to lead.
The "great leader" model of the presidency is extraordinarily dangerous. President Obama proves it each and every day; it's what gives him the power to tell our enemies that he'll have more "flexibility" after his "last election." He's our leader; we're his followers. It's that easy to him.
Fortunately, the Constitution doesn't allow for such egotism acted out in policy. The Constitution requires checks and balances. It requires that we battle out each and every policy change, that we compromise, deadlock and stall. Getting things done is not so important as getting the right things done. And nobody has a monopoly on what the "right thing" is -- no person and certainly no one branch of government.