Nonprofit national veterans organization AMVETS submitted an ad to be featured in the printed program set to be handed out at this year's Super Bowl, but the NFL shut it down, according to the LA Times. The ad in question was to be a full page, and would feature a picture of the American flag with the words, "Please Stand."

"While we are well aware of the controversy surrounding players kneeling during the National Anthem and the public relations problems this has caused the NFL, our ad is neither a demand nor a judgment upon those who choose to kneel during the National Anthem," wrote AMVETS National Commander Marion Polk in a letter addressed to NFL Commissioner Roger Goodell on Monday.

"It's a simple, polite request that represents the sentiment of our membership, particularly those whose missing or paralyzed limbs preclude standing. We sought to give a new context to the discussion from the perspective of veterans who had been largely disregarded," the letter continued.

After failing to get the NFL to approve the ad, Polk took to Twitter to express his frustration, accusing the football organization of violating their free speech rights.

My letter to @nflcommish & the @NFL. Let’s remember that freedom of speech works both ways. #PleaseStand https://t.co/CAWVFGbrKE pic.twitter.com/6LscJmUkJP— Marion Polk (@AMVETSNatlCmdr) January 22, 2018

.@AMVETSHQ will NOT tolerate the @NFL refusing #Veteran right to free speech. We fought for it! #PleaseStand #SuperBowl pic.twitter.com/NARbC5zKuE— Marion Polk (@AMVETSNatlCmdr) January 22, 2018

"The Super Bowl game program is designed for fans to commemorate and celebrate the game, players, teams and the Super Bowl. It's never been a place for advertising that could be considered by some as a political statement," NFL spokesman Brian McCarthy told 13WHAM this week.

McCarthy also claimed that the league tried unsuccessfully to work with AMVETS to create a new ad that met the NFL's advertising standards.

"We looked to work with the organization and asked it to consider other options such as "Please Honor our Veterans," McCarthy said. "They chose not to and we asked it to consider using 'Please Stand for Our Veterans.' Production was delayed as we awaited an answer."

The Veterans of Foreign Wars organization submitted a similar ad with different wording ("We Stand for Veterans"), and their ad was approved.

Please Stand

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