Is taking a knee protected speech?

Source: LewRockwell.com
by Andrew P Napolitano

"Sometimes the public expression of unwanted ideas reaches directly into our living rooms. When President Donald Trump attacked a half-dozen or so professional football players who, instead of standing during the traditional playing of the national anthem prior to football games, 'took a knee' by kneeling on one or both of their knees during the anthem, hundreds more players on national television took a knee in defiance of the president. Here is the back story." (10/12/17)

https://www.lewrockwell.com/2017/10/andrew-p-napolitano/is-taking-a-knee-protected-speech/