By Eric Marrapodi, CNN Belief Blog Co-Editor

Apology not accepted.

The Family Research Council, a conservative Christian advocacy group, is turning up the heat on NBC after it edited out "under God, indivisible" - twice - during a taped piece of children reciting the Pledge of Allegiance as part of last weekend's final round coverage of the U.S. Open Golf Championship.

The group wants to see the pledge recited on NBC, in its entirety, daily.

The criticism on social media over the golf gaffe came fast enough that NBC issued an on-air apology Sunday a few hours later during its coverage.

NBC lead golf commentator Dan Hicks told the audience, "Regrettably, a portion of the Pledge of Allegiance that was in that feature was edited out. It was not done to upset anyone, and we'd like to apologize to those of you who were offended by it."

On Monday, NBCUniversal Sports issued a second apology from Chris McCloskey, its vice president of communications.

He said in part, that a "decision was made by a small group of people to edit portions of the Pledge of Allegiance. This was a bad decision." And he again apologized if the deliberate omission upset anyone.

But that did not satisfy the Family Research Council.

Now the council is urging its members to contact NBC and demand the network play a public service announcement featuring the Pledge of Allegiance, in its entirety, daily.

"NBC must remedy this abuse by airing a series of public service announcement(s) with the entire Pledge of Allegiance," read an e-mail blast sent Tuesday from council President Tony Perkins.

"Please join me in contacting NBC and demanding that the network air a daily public service announcement with the entire Pledge of Allegiance."

The Washington-based Family Research Council says its mission is to advance "faith, family and freedom in public policy and public opinion." The group is best known for its strong objections to same-sex marriage and abortion. It's a powerful political force among conservative evangelicals.

"This is something that people, they get and they're upset about it," Perkins told CNN. "We know that 15,000 people have already sent e-mails to NBC. Based on the calls I got this morning, this is something people are incensed over."

Perkins said he did not watch the event live. He said he is not a big golf fan but was alerted to the omission quickly. He said he found the use of military images with the pledge omission particularly galling. "As a veteran I stood for the pledge and I stood for all of the pledge," the retired Marine said.

"These types of things need to be met with significant resistance," he said when asked if his group was leveraging this controversy for its own gain. "It's not up to NBC to change the pledge of the United States of America."

The phrase "under God" was not always in the Pledge of Allegiance.

The pledge was written by Francis Bellamy, a former Baptist minister who had left the pulpit and was working at a magazine, Youth's Companion. The magazine was putting together a nationwide celebration to honor Columbus discovering the New World. The pledge was expressly patriotic according to author and political scientist Richard Ellis in "To the Flag: The Unlikely History of the Pledge of Allegiance."

The pledge and the protocol for the pledge did not make it into U.S. law until June 22, 1942.

The phrase "under God" was added in 1954. Rep Louis Rabaut, D-Michigan, offered an amendment to add the phrase to the pledge. It was a homage to President Abraham Lincoln who had famously used it in the Gettysburg Address.

Rabaut testified before the House Judiciary Committee in 1954 why he thought it should be added because, "By the addition of the phrase 'Under God' to the pledge the consciousness of the American people will be more alerted to the true meaning of our country and its form of government," he said.

"In this full awareness we will, I believe, be strengthened for the conflict now facing us and more determined to preserve our precious heritage."

President Dwight D. Eisenhower signed the bill into law on Flag Day in 1954.

The pledge has been challenged in court, in particular the fact that children are instructed to recite it in public schools. Plaintiffs have argued that infringed on a student's First Amendment rights, citing the establishment clause, commonly referred to as "the separation of church and state."

The Supreme Court ruled the phrase was constitutional in 2004.

In that decision, Justice Sandra Day O'Connor wrote in a concurring opinion, "Whatever the sectarian ends its authors may have had in mind, our continued repetition of the reference to 'one Nation under God' in an exclusively patriotic context has shaped the cultural significance of that phrase to conform to that context. Any religious freight the words may have been meant to carry originally has long since been lost."

Perkins said in addition to the public service announcement of a daily Pledge of Allegiance he said he would also like to see NBC produce a program explaining the history of the pledge and why "under God" was inserted in the first place.

NBC hasn't responded to Perkins about his requests. A spokesman for the network declined to comment further on the matter.