Quarterback Colin Kaepernick isn’t the first athlete to make a political protest when the spotlight is on him. John Carlos and Tommie Smith famously raised a black power salute as they received their medals in the 1968 Olympics; Muhammad Ali sacrificed his heavyweight title to protest the Vietnam War. Kaepernick, who has been refusing to stand for the National Anthem before San Francisco 49ers games, hasn’t suffered repercussions as serious as those who came before him, but he has been strongly criticized. Those who praise Ali while denouncing Kaepernick are inconsistent, if not hypocritical.

Nor will Kaepernick be the last to engage in this kind of protest. A Denver Broncos player took a knee during the anthem at the NFL opener Thursday. College athletes have begun doing the same thing, and we expect to see more. Kaepernick’s protest resonates loudly in minority communities and on campus.

Protesting a symbol — like the flag or the national anthem — can be problematic. Because symbols mean different things to different people, the protest can easily be misinterpreted. Some resent bringing politics into an event that is supposed to divide people by team loyalties, not political preferences. But symbolic protests generate more emotion, and televised football games get more attention. Kaepernick could have expressed his opinions more specifically in a letter to the editor or marched in the streets with others who share his position, but would anyone have noticed?

The loudest objection we’ve heard is that Kaepernick’s protest is a sign of disrespect to America’s military, which is curious. The flag stands for the whole country, not just its troops. The military’s job is to defend the flag, not the other way around.

Besides, Kaepernick has said his decision to take a knee during the National Anthem has nothing to do with America’s troops, either those who defended the country in the past or those serving in uniform today. He has made it very clear that he is protesting institutional racism in general, and racial disparities in criminal law enforcement in particular. He believes African-Americans are disproportionately targeted and harmed by the police. That’s a position backed up by some data, a pile of anecdotes and a damning collection of videos.

It appears woven into the American fabric that each generation must rediscover racial injustice in our nation’s past and present. Kaepernick’s generation is coming to grips with that legacy, and demanding it be discussed — in the streets, on campus and now, at football games. Other Americans should join that discussion, not try to shout it down.

As President Barack Obama noted this week, raising these issues is Kaepernick’s constitutional right, however he chooses to make his protest. For those who think Obama’s words of support also somehow show disrespect the troops, we should remember that the president takes an oath to defend the Constitution, not to defend the military from imaginary slights.

The flag doesn’t fly for soldiers alone. It flies for protesters as well.