The controversial statements — made during a rally Friday in Alabama and in a series of tweets over the weekend — spurred widespread outrage online, and prompted even more protests during the weekend’s NFL games.
Players have been peacefully protesting racism in the United States by taking a knee during the national anthem ahead of football games, a movement player Colin Kaepernick began by refusing to stand for the anthem at a game in 2016.
According to the U.S. Code’s “Flag Code” section, which was unveiled in 1924, all those present during a national anthem, flag hoisting, lowering or passing, should stand at attention with their right hand over their heart. But the conduct does not mention specific rules surrounding kneeling or peacefully protesting.
WATCH: “I think the owners should do something about it,” Trump says on NFL players kneeling during anthem
While the president took issue with this form of “disrespect” toward the flag, rules on how Americans should act around their country’s flag are regularly broken.
Here are some ways Americans have “disrespected” the flag, according to the federal code.
Wearing the flag
“The flag should never be used as wearing apparel, bedding, or drapery. It should never be festooned, drawn back, nor up, in folds, but always allowed to fall free,” the code reads.
That means flag shirts, scarves, swimsuits are all considered disrespectful, even though they are widely accepted.
Here’s Trump’s Interior Secretary Ryan Zinke wearing socks printed with the American flag to a meeting:
Carrying the flag horizontally
The American flag should always be vertical, and never carried horizontally, but it is regularly carried that way during sporting events.
Using the flag as a marketing prop
“The flag should never be used for advertising purposes in any manner whatsoever.”
But it often is — especially during Fourth of July celebrations. From packaging for fireworks to TV commercials, the American flag is regularly used.
Here’s a pack of fireworks being sold in California on July 3, 2014:
Here are hot sauce bottles sold ahead of Trump’s inauguration in January:
Drawing on the flag
Changing the flag, or assigning an additional message to it, is strictly prohibited.
“The flag should never have placed upon it, nor on any part of it, nor attached to it any mark, insignia, letter, word, figure, design, picture, or drawing of any nature.”
But this is often done, notably during protests.
And at Trump’s inauguration.
Flags on athletic uniforms
Here’s another way sports often disrespect the flag. The U.S. flag is not meant to be displayed on athletic uniforms, but there are several examples of this happening.
“No part of the flag should ever be used as a costume or athletic uniform.”
During the Olympic games, for instance:
However, a flag patch is allowed for other uniforms, such as military officers, firemen and policemen.