"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."
Did you notice what's missing? Let me give you some help. There is no "so help me God" written in the oath and the words "God" nor "Creator" do not appear anywhere in the US Constitution. Likewise, the Pledge of Allegiance was modified in 1954 at the height of the McCarthy era when the fear of communism inspired some Americans to violate our separation of church and state by including the words "under God".
"I pledge allegiance to the Flag of the United States of America, and to the republic for which it stands; one Nation indivisible with liberty and justice for all."The modified version:
"I pledge allegiance to the Flag of the United States of America, and to the republic for which it stands, one Nation under God, indivisible, with liberty and justice for all."
Attempts to remove these augmentations have been met with stiff resistance mostly from theists who complain of the secularization of the US by godless atheists. But us godless atheists really just want to see our nation get back to being a secular democracy as it originally was, as intended by our founding fathers.
The communism scare of the fifties was also when the phrase "In God We Trust" got stamped onto our paper currency, replacing the previous motto, "E pluribus unum" or "Out of many, one". In 1956, the 84TH UNITED STATES CONGRESS passed Public Law 84-851 which declared that the national motto of the US to be "In God We Trust". While not exactly establishing a religion as the first amendment prohibits, this is a form of "ceremonial deism" forcing others to officially recognize god.
So when secularists fight against these intrusions of god into our official government, they are really just fighting to make our country as secular as it originally was. Some anti-secularists forget that these mentions of "God" were inserted years later often as attempts to make the US appear as a god-fearing nation to distinguish it from the godless communists. There are also people who actually think that if we acknowledge god, he will aid the United States and protect Americans from enemies during wars and conflicts. These are the people that also believe that god in the Old Testament chooses sides with tribes at war and that the outcome of what tribe won the war depended on what side god was on. Many of these people are in Congress and have occupied the White House. This has me concerned. I'm weary of elected officials who think that trying to make America as much of a Christian nation as possible will somehow ensure its people's prosperity into the future. These are the same lawmakers however who are lining the pockets of big business and are doing almost everything they can to cash in on opportunity of getting rich, while sending the future of American down the drain. It makes little moral sense for the god-fearing, but that's another story.