I doubt that Obama will be the first modern president to return to the actual text of his oath from the Constitution and, if he does, it’ll likely be for the wrong reason. I also don’t expect him to honor it in the slightest.
But if you think George Washington was the first to add the “so help me God” language, you’re likely mistaken.
Taken together, the complete lack of contemporary evidence, George Washington’s political philosophy of strictly following the Constitution and the concurrent debate over the proper wording of oaths under the new Constitution make it virtually certain that George Washington did not add the words “So help me God” to his inaugural oath.
No, I’m not a Newdow Atheist (ie: litigious busybody) but I do believe the Constitution says what it means, and that it is the most important single document in the country. This is the only sentence in the whole document which is in quotes:
“I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.”
That’s what the Founding Fathers meant the president to say, and that’s what he should say. No more, no less.