NFL Commissioner Roger Goodell said Tuesday the league had a plan to "move past" the roiling debate over player protests during the national anthem, a growing political firestorm that he said was "threatening to erode the unifying power of our game."

In a letter to team owners, Goodell said the league respects the right of its players to express their views on "critical social issues," but he suggested the league thinks athletes should not take a knee during "The Star-Spangled Banner."

NFL commissioner Roger Goodell answers reporter's questions on May 24, 2016. Bob Leverone / AP

"Like many of our fans, we believe that everyone should stand for the national anthem," Goodell wrote. "It is an important moment in our game. We want to honor our flag and our country, and our fans expect that of us."

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The league, working with teams and players, has "worked to develop a plan" that it will present at a league meeting next week, Goodell said. That plan will include an "in-season platform to promote the work of players" on social issues, and "help to promote positive change in our country."

Goodell's letter came just hours after President Donald Trump, in an early morning tweet, suggested he would try using the IRS to punish the NFL — emphatically writing, "change tax law!":

Why is the NFL getting massive tax breaks while at the same time disrespecting our Anthem, Flag and Country? Change tax law! — Donald J. Trump (@realDonaldTrump) October 10, 2017

The issue has divided football fans since last season, when quarterback Colin Kaepernick, then with the San Francisco 49ers, refused to stand for the anthem as a way of protesting what he viewed as police brutality and the systemic oppression of black people in America.

Trump intensified the debate over anthem protests last month when, during a freewheeling speech in Alabama, he said the league should fire players who kneel during the anthem. Goodell, at the time, criticized Trump's comments as lacking respect for the league and its players.

The battle escalated this week after Vice President Mike Pence walked out of an Indianapolis Colts game Sunday afternoon after members of the visiting 49ers knelt during the anthem. Hours later, Dallas Cowboys owner Jerry Jones suggested that players who are "disrespectful" to the American flag should not be allowed to play.

Related: Can Cowboys Owner Jerry Jones Bench a ‘Disrespectful’ Player?

"If there is anything that is disrespectful to the flag then we will not play," Jones said, according to The Dallas Morning News. "You understand? If we are disrespecting the flag then we will not play. Period."

Two players on the Cowboys had raised their fists after the anthem on Sunday. Jones said he was not aware of that act of defiance. The Cowboys declined to elaborate on the remarks of its owner.

On Monday, ESPN suspended analyst Jemele Hill after she suggested in a series of tweets that fans should boycott the Cowboys' advertisers as a way of showing displeasure with Jones' comments.

Also on Monday, former NFL coach and ESPN analyst Mike Ditka suggested the social justice issues driving the NFL protests were overblown, telling a radio interviewer on Westwood One that "there has been no oppression in the last 100 years that I know of."