It has been nearly three weeks since critical comments from President Donald Trump ignited a wave of national anthem protests across the NFL, and the opposition to the movement doesn't appear to be going away any time soon.

Dallas Cowboys owner Jerry Jones and former head coach and current commentator Mike Ditka were among the big names to come down hard against the protests this week, while Vice President Mike Pence walked out of Sunday's game between the Indianapolis Colts and San Francisco 49ers after several players dropped to one knee.

Now, the league itself is weighing in on the issue, outlining their official policy on the national anthem for the first time to ESPN's Chris Mortensen, who reported it prior to Monday night's game between the Minnesota Vikings and Chicago Bears.

The policy, which is outlined in the league's operations manual and which was only recently made available online, notes that players "should" stand for the anthem and are "judged by the public" for their actions during the ceremony. It also threatens disciplinary action "for violations of the above, including first offenses" (via Kevin Seifert).

That policy doesn't seem out of line with the views of power brokers around the NFL, but it does differ from the rules listed in the league's "Policy Manual for Member Clubs" from 2014, retrieved by Deadspin.

According to the text:

The National Anthem must be played prior to every NFL game, and all players must be on the sideline for the National Anthem. During the playing of the National Anthem, players on the field should stand at attention, face the flag, hold helmets in their left hand, and refrain from talking. Players in the bench area should do the same and should line themselves up evenly along the sidelines. The home team should ensure that the flag is in good condition. It should be pointed out to players and coaches that we continue to be judged by the public in this area of respect for the flag and our country. Failure to be on the field by the start of the National Anthem may result in disciplinary action from the League office.

The NFL has not disciplined any national anthem protestors to date.

According to Nancy Armour of USA Today, the changes were made in 2015, which would even predate the first time Colin Kaepernick did not stand for the anthem.

The national anthem protestors may be in violation of both policies, although the vague nature of the word "should" is going to lead to debate on the topic and will certainly be used by players to fight any punishment if the league decides to do so. The languange saying teams "must" be on the field during the anthem is more clear and several teams have already seemingly violated this policy.

It's also worth noting how the language has changed in the last three years. The newer rule outlines specific, strict punishments, including the forfeiture of draft picks, while the older version granted disciplinary power explicitly to the league office.

Curiously, Trump seems to have had a hand in bringing the revised policy to light. Jerry Jones said Trump reminded him of the league's game operations manual, according to Mortensen.