How Trump and Obama handled MAGA chants shows how much American politics has changed in just three years.

I'm staring at my screen watching the President of the United States speak before a stadium full of people in North Carolina. He launches into a lie-laced attack on Congresswoman Ilhan Omar, and the crowd boos. Soon they start chanting, "Send her back! Send her back! Send her back!"

The President does nothing. Says nothing. He just stands there and waits for the crowd to finish their outburst.

WATCH: Trump rally crowd chants 'send her back' after he criticizes Rep. Ilhan Omarwww.youtube.com

My mind flashes to another President of the United States speaking to a stadium full of people in North Carolina in 2016. A heckler in the crowd—an old man in uniform holding up a TRUMP sign—starts shouting, disrupting the speech. The crowd boos. Soon they start chanting, "Hillary! Hillary! Hillary!"

The President shuts it down. "Hold up! Hold up!" he repeats, admonishing the crowd to sit down and be quiet. He comes to the heckler's defense, saying that the man is just supporting his chosen candidate. Then he tells his supporters:

"Now listen up…First of all, we live in a country that respects free speech. Second of all, it looks like maybe he might have served in our military, and we've got to respect that. Third of all, he was elderly and we've got to respect our elders. And fourth of all, don't boo—vote!"

President Obama not only defended the rights of this man who disagreed with him, but he defended the Constitution, defended the military, defended the elderly, and defended democracy, all at the same time. He told his followers to treat a political adversary with respect. He shut down the frenzy and encouraged people to focus, not on distractions and detractors, but on the issues at hand.

A day—and a great deal of backlash later—Trump said he "wasn't happy" when the crowd started chanting. But he did nothing to try to stop it, and he offered no apology for it.

Using the 'dictionary definition of racism' defense is a sure sign you don't understand racism.

The contrast in leadership could not be more stark.

Though horrible, nothing about the "Send her back" chants at that rally should be surprising. Did anyone who has watched the Muslim travel ban, the "immigrant crimes" hotline, the horrendous family separations, the inhumane detention conditions, and the severe limitations on asylum seekers really think that illegal immigrants were really going to be the President's only target?

Omar is a legal immigrant who arrived through our refugee program as a child and became an American citizen at 17. She's from a working-class family in the Midwest who raised her to love and appreciate democracy. Despite being constantly accused of "hating America," she speaks out clearly in defense of the Constitution and the country.

She isn't afraid to "tell it like it is" from her perspective (which is what people say they love about Trump). Though she has made a few statements that were construed by some as anti-Semitic, she has publicly apologized (while also explaining that criticizing the Israeli government is not the same as being anti-Jewish).

However, she's black, she's Muslim, and she disagrees with Donald Trump. And that is enough, in 2019, for the President to stand idly by while thousands of people chant an ethnic slur about a sitting member of Congress and a U.S. citizen. As opposed to merely a political adversary, Trump paints Omar as an evil presence and threat to our nation, repeating baseless conspiracy theories about her. That is not only unbecoming of the office of the Presidency; it also directly endangers the Congresswoman's safety.

If the footage of that rally doesn't disgust you, you are on the wrong side of history. There is no other way to slice it. If you find it exciting when a rabid crowd of people calls for a former refugee and freely elected representative in our government to be returned to the country of her birth, then you are the antithesis of everything America stands for.

I love my country, and what I saw in that rally was nothing close to patriotism—it was bigotry, xenophobia, prejudice, intolerance, and sycophancy. It made me feel ashamed as an American. It made me want to tell the world that we are better than this, but the evidence on my TV screen screams otherwise. I want people to know that those people chanting those hateful words don't represent the majority of Americans—but honestly, that remains to be seen.

Any student of history knows that populations slide into fascism willingly, even if unwittingly. We are not immune to the pull of our basest instincts, especially when they are purposefully played upon by despots. Prejudice has always been a powerful weapon wielded by unscrupulous people who know it's the easiest way to sway a populace to do their bidding.

Trump just bizarrely claimed Arnold Schwarzenegger had 'died.' An unfazed Arnold flexed back.

As Nazi military leader Hermann Goering said, "All you have to do is to tell them they are being attacked, and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same in any country." It's a simple, winning formula. And we are watching it unfold before our eyes.

Where will the line be, America? At what point will we collectively decide that it's gone too far? When the government demonizes and scapegoats an entire category of people? Already happening. When we start putting people into camps? Already happening. When people actually start dying in them? Also happening. When the government starts attacking U.S. citizens? Oh, happening.

The signs are clear. We're not at a precursor stage—we are in it. This goes far beyond partisan politics, far beyond debating about policy. This is about who we are at our core and what we allow ourselves to become as a nation.