A constitutional amendment that John B. Anderson, a born-again Christian, proposed early in his congressional career has come back to haunt his independent presidential candidacy.

The amendment would have put the United States on record as "devoutly" recognizing "the authority and law of Jesus Christ, savior and ruler of nations, through whom are bestowed the blessing of almighty God."

Had it been adopted, the amendment would have reordered the nation's tradition posture toward separation of church and state in favor of Christianity.

"It is an insult to all people who aren't of his particular faith. It runs contrary to all our concepts of a pluralistic society," said Leon Shull, national director of Americans for Democratic Action, a liberal group. "Maybe after he makes the country Christian, he would like to make it Protestant, and then maybe evangelical," he said, referring to Anderson's religion.

Coincidentally, it has been the supporters of another born-again Christian, President Carter, who seized on the issue. Fearful that Anderson's independent presidential candidacy may damage the president next fall, they have initiated a campaign to discredit the Illinois congressman among liberals and minority groups.

When he was asked about the amendment in March by the Detroit News, Anderson dismissed it as a foolish act of a naive freshman congressman and said he had only introduced it on one occasion.

But later it was learned that the Illinois Republican introduced the same resolution not only in 1961, his first year in Congress, but also in 1963 and in 1965.

Asked about the amendment Friday, Anderson said: "It was a dumb thing to do and I shouldn't have introduced it. I'm now politically embarassed by it, and Mr. Strauss [Robert Strauss, Carter's campaign director] will see to it that I'm more embarrassed by it as every week and month goes by."

The amendment, which was sponsored by about 25 other congressmen, died quietly in the House Judiciary Committee.

"I never testified on it," he said. "I never made any speeches on it. I never lobbied for it. I never talked to a member of the House Judiciary Committee about it."

Anderson, who is trying to attract support among liberals, said he was persuaded to introduce the bill by a kindly clergyman who convinced him it would be a good way to reestablish "in these very pagan times the fact that our nation was founded, not by free booters, but rather by godly men and women."

The first two sections of the three-part amendmant prohibited the establishment of a state religion and gave non-Christians the right to refuse to swear allegiance to Christianity.

But it was the first section, which "devoutly recognized the authority and law of Jesus Christ," that troubles libertarians.

"It is a surprising position for Anderson to take," said John Shattuck, director of the Washington office of the American Civil Liberties Union.

"It seems very much at odds with his current position on civil rights issues. We rate him very high."

Anderson today began his first compaign swing outside of Washington since he anounced Thursday he was dropping out of the race for president as a Republican and running as an independent. It was a leisurely, low-key trip. He scheduled only two public appearances in two days.

In a speech to a conference of NAACP women here, he called for a redistribution of wealth of the oil- and gas-rich states of the South and West to decaying urban centers of the Midwest and Northeast.

One of the toughest tasks facing the next president, Anderson said, "will be to find ways of making sure we don't become a nation that is divided between rich and poor along sectional lines, or that we do not have a permanent impoverished underclass living in the great cities of the Northeast and upper Midwest."