Attorneys general from all 50 states -- weighing in ahead of a federal hearing on Thursday -- called an atheist-led lawsuit to stop the religious rites at next week's inauguration bunk.
The lawsuit -- filed late last month by Michael Newdow -- seeks to prevent religious prayers as part of the official ceremony. It also attempts to pre-empt Chief Justice John Roberts from adding the words "so help me God" to the inaugural oath.
The hearing is set to go before Judge Reggie Walton in the United States District Court in Washington, D.C.
In a 21-page brief filed late Monday, the attorneys general called for the case to be dismissed, arguing that, "prayers and oaths invoking God have been a staple of official inaugural events throughout history, across the country, and at every level of our government."
"Plaintiffs cite no legal authority that permits, let alone requires, this Court to interfere with the content and conduct of the solemn occasion that our President-elect and his staff have so carefully planned, and that millions of Americans so eagerly anticipate," the court papers read.
The brief also notes that 26 states currently have the words, "So help me God" proscribed in the official oath of office for various state positions, including governor.
"Plaintiffs' breathtaking effort to eliminate our nation's most cherished traditions finds no basis in the Constitution, Supreme Court precedent, or historical custom," the brief says.
This is not the first time Newdow -- best known for losing a Supreme Court challenge to the words "under God" in the Pledge of Allegiance -- has filed lawsuits challenging religious offerings at inaugurals.
He failed in his efforts to do the same for the 2001 and 2005 inaugurations of George W. Bush.
"[Newdow's] complaint here suffers from the exact same defects that doomed Mr. Newdows previous litigation efforts," wrote Justice Department lawyers in court documents filed last week. The challenge to the oath was not part of the earlier lawsuits.
The government is representing Chief Justice Roberts, who is expected to follow tradition and administer the presidential oath. That oath is required under Article II, Section I of the Constitution, but the phrase, "so help me God," does not appear.
According to legend, George Washington unexpectedly added it at his inauguration -- though the historical accuracy of this is uncertain. Every president since Franklin Roosevelt has asked for the heavenly assistance, and President-elect Barack Obama has requested it as part of his oath.
Newdow and the others who filed the lawsuit believe Roberts "will (with no authority whatsoever) alter the text of that document to infuse the inaugural ceremony with purely religious dogma."
They also believe they have a First Amendment protection against the inclusion of religious prayers from the upcoming event. Reverends Rick Warren and Joe Lowery have been asked to give an invocation and benediction.
The Presidential Inaugural Committee, which is in charge of running the proceedings on January 20th, is named in the suit. But the committee has argued that the lawsuit against is pointless. In their brief to Judge Walton, the Presidential Inaugural Committee said the ultimate decision with the oath of office rests with Obama.
Newdow said he has no plans at this time to challenge Mr. Obama's right to add the words at the end of the oath. His lawsuit focuses on the Chief Justice's administration of an oath that includes "so help me God."
But government lawyers say Newdow's argument is nonsensical.
"[Newdow's] legal theory -- that the president of the United States has a First Amendment right to say the words 'so help me God' after taking the oath of office, but not to have the same affirmation administered to him -- simply makes no sense," said Justice Department trial lawyer Brad P. Rosenberg.