In the United States, the 
Pledge of Allegiance has been a part of American life since 1942 when congress 
passed the Flag Code into law, describing the proper ways to display and treat 
the nation's flag. 
1 At that time, the pledge did not 
contain the words "under God" in it. It also originally stipulated that citizens 
should say the pledge with their right hands outstretched toward the flag. 
However, given that salute's eerie similarity to the Nazi salute, the wartime 
congress quickly amended the law to have citizens place their right hands over 
their hearts. 
2
It wasn't until 1953, when Democratic 
 Congressman Louis Rabaut and Republican Senator Homer Ferguson introduced a 
bill to congress to amend the Pledge to include the words "under God" that the 
national debate was brought center stage. During this time, many different 
voices contributed to the debate. While a lot of media today explain away the 
addition as simply a knee-jerk response to those "Godless communists" in the 
Soviet Union, I think there is much more to the addition than that. Several 
civic groups, most noticeably the Roman Catholic Knights of Columbus had decided 
to include the phrase in their recitation of the Pledge a few years prior, 
modeling it after Abraham Lincoln's use of the term in his Gettysburg address.
3 
Other groups began to do likewise.
God and the Constitution
In general, the question of how God relates to American government was 
swirling at the time. In 1952, the U.S. Supreme Court had just decided a case 
(Zorach v. Clauson, 343 U.S. 306) stating school children should be excused from 
attending public school for reasons of religious education or religious 
observance. Justice William O. Douglas, in writing for the majority said:
The First Amendment, however, does not say that in every and all respects 
 there shall be a separation of Church and State. Rather, it studiously 
 defines the manner, the specific ways, in which there shall be no concern or 
 union or dependency one on the other. That is the common sense of the 
 matter. Otherwise the State and religion would be aliens to each 
 other—hostile, suspicious, and even unfriendly…
We are a religious people 
 whose institutions presuppose a Supreme Being. We guarantee the freedom to 
 worship as one chooses. We make room for as wide a variety of beliefs and 
 creeds as the spiritual needs of man deem necessary. We sponsor an attitude 
 on the part of government that shows no partiality to any one group and that 
 lets each flourish according to the zeal of its adherents and the appeal of 
 its dogma. When the state [343 U.S. 306, 314]  encourages 
 religious instruction or cooperates with religious authorities by adjusting 
 the schedule of public events to sectarian needs, it follows the best of our 
 traditions.4
Liberty Relies on the Natural Rights that God Bestows
As one can see, it was widely recognized that the United States was a nation 
founded upon certain principles, and those principles had at their root the 
belief that God exists and he is the source of those natural rights that this 
country holds so dear. 
Such a concept shouldn't be shocking to anyone who 
has read the Declaration of independence. Even though Thomas Jefferson was a 
deist, he recognized that God alone grounds our rights. In writing about the 
revolution, he said "The god who gave us life gave us liberty at the same time: 
the hand of force may destroy, but cannot disjoin them."
5 Jefferson in another letter goes on to reinforce this view. When speaking on the issue of slavery, one that had begun to divide the nation, he said:
And can the liberties of a nation be thought secure when we have removed 
 their only firm basis, a conviction in the minds of the people that these 
 liberties are of the gift of God? That they are not to be violated but 
 with his wrath? Indeed I tremble for my country when I reflect that 
 God is just: that his justice cannot sleep for ever. 6
Because the liberties of Americans depend on God and the foundational 
recognition that all governments must be held to this standard, which is a 
standard above themselves, the pressure increased to add the words "under God" 
to the pledge.
A New Birth of Freedom
On Feb 7, 1954, President Dwight Eisenhower attended a 
service at New York Avenue Presbyterian Church where he heard Rev. George 
Docherty deliver a sermon entitled "A New Birth of Freedom," highlighting this 
distinction and drawing on Lincoln's Gettysburg Address. While Docherty did say 
"I could hear little Muscovites repeat a similar pledge to their 
hammer-and-sickle flag in Moscow with equal solemnity," to assume that was the 
focus of his reasoning would be to do him and President Eisenhower a disservice. 
You may real Docherty's
entire sermon here, but for conciseness, here is the relevant portion:
There is no religious examination on entering the United States of America- 
 no persecution because a man's faith differs even from the Christian 
 religion. So, it must be 'under God' to include the great Jewish Community, 
 and the people of the Moslem faith, and the myriad of denominations of 
 Christians in the land.
What then of the honest atheist?
Philosophically speaking, an atheistic American is a contradiction in terms. 
 Now don't misunderstand me. This age has thrown up a new type of man-we call 
 him a secular; he does not believe in God; not because he is a wicked man, 
 but because he is dialectically honest, and would rather walk with the 
 unbelievers than sit hypocritically with people of the faith. These men, and 
 many have I known, are fine in character; and in their obligations as 
 citizens and good neighbors, quite excellent.
But they really are 
 spiritual parasites. And I mean no term of abuse in this. I'm simply 
 classifying them. A parasite is an organism that lives upon the life force 
 of another organism without contributing to the life of the other. These 
 excellent ethical seculars are living upon the accumulated spiritual capital 
 of Judeo-Christian civilization, and at the same time, deny the God who 
 revealed the divine principles upon which the ethics of this country grow. 
 The dilemma of the secular is quite simple.
He cannot deny the Christian 
 revelation and logically live by the Christian ethic.
And if he denies 
 the Christian ethic, he falls short of the American ideal of life.
In 
 Jefferson's phrase, if we deny the existence of the god who gave us life how 
 can we live by the liberty he gave us at the same time? This is a 
 God-fearing nation. On our coins, bearing the imprint of Lincoln and 
 Jefferson are the words "In God we trust." Congress is opened with prayer. 
 It is upon the Holy Bible the President takes his oath of office. 
 Naturalized citizens, when they take their oath of allegiance, conclude 
 solemnly, with the words "so help me God."
This is the issue we face 
 today: A freedom that respects the rights of the minorities, but is defined 
 by a fundamental belief in God. A way of life that sees man, not as the 
 ultimate outcome of a mysterious concatenation of evolutionary process, but 
 a sentient being created by God and seeking to know His will, and "Whose 
 soul is restless till he rest in God."
In this land, there is neither Jew 
 nor Greek, neither bond nor free, neither male nor female, for we are one 
 nation indivisible under God, and humbly as God has given us the light we 
 seek liberty and justice for all. This quest is not only within these United 
 States, but to the four corners of the glove wherever man will lift up his 
 head toward the vision of his true and divine manhood.7
After that sermon, President Eisenhower went to congress and asked them to 
reintroduce the amendment to the Flag Code, which he signed into law on May 28, 
1954. 
References