Here's a campaign promise the White House would like to forget: In 2008, then-Senator Barack Obama promised to reverse what he saw as "one of the biggest problems" facing America - the president using his executive power to bypass Congress.

"I taught constitutional law for 10 years. I take the Constitution very seriously," Obama said during a campaign rally in Lancaster, Pa., on March 31, 2008. "The biggest problems that we're facing right now have to do with George Bush trying to bring more and more power into the executive branch and not go through Congress at all."

And then came the promise: "And that is what I intend to reverse when I become president of the United States."

Now, of course, Obama is vowing to do precisely what he criticized Bush for doing: using the power of the presidency to act where Congress won't.

The video is striking - and not just because Obama has absolutely no gray hair. Substitute the words "President Bush" with "President Obama" and he sounds precisely like Republicans today.

VIDEO: http://abcn.ws/LYngLy

Today it is the Republicans echoing Senator Obama from 2008 who are accusing the president of violating the Constitution and grabbing power that rightfully belongs to Congress. Back then, of course, many Republicans defended President Bush for asserting executive power in the face of they called an obstructionist Congress.

None of this would have surprised Rufus Miles.

Miles was a mid-level bureaucrat in the Truman administration when one of his colleagues reluctantly left his agency to work for another. Within months of his goodbye, the official had become a turncoat: critical of his old colleagues and defensive of his new ones. Miles had predicted this would happen, telling a co-worker, "You see, it depends on where you sit, how you stand." He eventually refined the phrase to "where you stand depends on where you sit" and it became known as Miles' Law.

So here we have a textbook example of Miles' Law - Barack Obama denounced the aggressive exercise of presidential power when the person exercising that power was a Republican and he was a Democrat in Congress. Now that he is the one exercising that power, he has a different view.