`` so help me God . '' It is not constitutionally required , unlike in other federal oaths . Historians have been at odds over whether George Washington established precedent by invoking the phrase on his own at the first inaugural in 1789 . The Library of Congress Web site says he did . Most presidents have used the phrase . iReport.com : Your photos from the inauguration Inaugural officials and presidents or presidents-elect usually coordinate behind the scenes on whether the judge or government official administering the phrase will invoke it . Michael Newdow , supported by several groups including the American Humanist Association , claims in his lawsuit that `` so help me God '' violates the constitutional ban on government `` endorsement '' of religion . He asked a federal judge to intervene and block references of God or religion in the formal ceremonies . The lawsuit also opposes the traditional invocation and benediction to be delivered by pastors invited by Obama . `` There can be no purpose for placing ` so help me God ' in an oath or sponsoring prayers to God , other than promoting the particular point of view that God exists
WASHINGTON -LRB- CNN -RRB- -- President-elect Barack Obama will invoke God when he takes the oath of office January 20 , despite a lawsuit filed by atheist and non-religious groups , according to an attorney for Chief Justice John Roberts , who will administer the oath . President-elect Barack Obama has asked to invoke the phrase `` so help me God '' at the end of his oath . The groups have sued in federal court to block any mention of God during the inaugural ceremonies . Roberts was among those named in the suit . However , Obama wishes to conclude the oath with the phrase `` so help me God , '' Jeffrey Minear , an attorney and administrative assistant for Roberts , told a federal court in documents Friday . The Constitution mandates the exact language to be used in the 35-word oath of office : `` I do solemnly swear -LRB- or affirm -RRB- 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 . '' Some chief executives have embellished the oath with