Most Americans can still remember where they were and what they were doing when the planes hit and the Twin Towers fell on Sept. 11, 2001.

The country was collectively horrified as the death toll mounted — the passengers on Flight 11 and Flight 175 which hit the towers, the workers in the New York City Trade Center buildings, the firefighters and police who rushed in to save them, the passengers and crew of Flight 93 which crashed in Shanksville, PA, and the passengers and crew of Flight 77 which hit the Pentagon. We remember the chaos, the tsunami of dust, smoke and debris that enveloped those who ran, and the horrifying realization that these acts were deliberate, the work of terrorists who infiltrated our country.

It was unimaginable.

Amid the shock and grief, Americans united, drawing strength from each other, helping where they could, buoyed as allies around the world extended solidarity with the U.S.

Except for the jihadists of al-Qaeda and their supporters, who rejoiced in the bloodshed.

We could not have imagined that such groups festered in their hated for America, the West and our values.

Neither could we have imagined 23 years later that “Death to America” would be chanted  in our streets – by Americans.

Yet here we are.

Anti-Israel protests following the Oct. 7 terror attacks there and subsequent Israel-Hamas war started with “Free Palestine” and anti-Jewish rhetoric, and have devolved to include the slogan “Death to America” across the country.

As FoxNews reported in April, students at the University of Michigan who were participating in such protests being given pamphlets titled “10 anarchist theses on Palestine solidarity in the United States,” which included a page that stated, “Freedom for Palestine means Death to America.”

When New York City police officers cleared out protest at New York University campus in May, they found signs with terrorist slogans at an encampment, according to the  New York Post.  One piece of literature found on the site explicitly called for “Death to America. ”  “Enough with De-Escalation Trainings: Where are the Escalation Trainings!” added another.

The students are back for fall semester, and those, like the Columbia University protests who chanted “We are Hamas!” this spring are back for more.

These are America’s children, malleable, ill-educated, eager to rebel and ripe for the propaganda pushed by progressive professors and Hamas cheerleaders. Most, if not all, were born after 9/11. They don’t remember what “death to America” looks like when terrorists turn that slogan into the mission statement of an attack that kills thousands.

They see flyers with the faces of the innocent Israeli and Americans kidnapped by Hamas and tear them off walls. They are ignorant of history, and enthusiastically parrot terrorist talking points as fact.

The America which united after 9/11 hoped for a better future for its children and was fearful that terrorists would dash these dreams. The idea that “death to America” would morph from a jihadi battle cry to a college protest anthem was inconceivable.

Just as the Holocaust should be required learning in U.S. colleges to stem the tide of antisemitic ignorance, so too should the events of 9/11 be a part of modern history curriculum.

We can’t let the terrorists win.

Editorial cartoon by Gary Varvel (Creators Syndicate)