Basketball great Kareem Abdul-Jabbar on Monday called the NFL’s new rule on standing during the national anthem “a disgrace to the Constitution.”

“To deny players the right to express their frustration in a peaceful manner is a disgrace to the Constitution, the opposite of patriotism,” Abdul-Jabber wrote to the Guardian. “By compromising ethics to economy, you show moral weakness. And if you think you’re appealing to your fan base, you might be doing the opposite.”

He suggested owners “don’t value your black players’ values” while they impose a “white perception” of America.

“You’re telling them that they must abide by your white perception of social justice even though you have no experience with the kind of institutional injustice that robs their community of lives, hope and a future,” Abdul-Jabbar wrote to the Guardian. “You are owners in that you own the franchise, but you don’t own the players or their hearts and minds.”

President Donald Trump has vociferously opposed kneeling during the anthem and has called out the practice at several pep rallies to supporters. The protest began in 2016 when then-San Francisco 49ers player Colin Kaepernick decided to use the anthem to make a statement about police abuse of power and racial unrest in America.

The league agreed to require players to stand, or stay in the locker room during the national anthem.

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