CNN  — 

A retired four-star Marine general on Wednesday excoriated President Donald Trump’s threats to use the military on protesters and his controversial church photo op on Monday, writing that his actions “may well signal the beginning of the end of the American experiment.”

Gen. John Allen, the former commander of American forces in Afghanistan and former special presidential envoy for the Global Coalition to Counter ISIS under the Obama administration, wrote in an op-ed for Foreign Policy that “to even the casual observer, Monday was awful for the United States and its democracy.”

His comments come after the President declared himself “your president of law and order” as peaceful protesters just outside the White House gates were dispersed with gas, flash bangs and rubber bullets, apparently so Trump could visit a nearby church. He remained at the boarded-up building for a matter of minutes before returning to the White House.

The episode followed nearly a week of protests across the country that at times have turned violent over the death of George Floyd, a 46-year-old African American man who died while in police custody in Minneapolis.

“Donald Trump isn’t religious, has no need of religion, and doesn’t care about the devout, except insofar as they serve his political needs. The President failed to project any of the higher emotions or leadership desperately needed in every quarter of this nation during this dire moment,” Allen wrote.

“We know why he did all this on Monday. He even said so while holding the Bible and standing in front of the church. It was about MAGA—’making America great again,’” he continued.

Allen told CNN’s Christiane Amanpour on Thursday that he watched Monday’s events unfold “with horror, frankly.”

“That is what happens in authoritarian regimes. That is what happens in illiberal regimes” he continued. “It doesn’t happen in the United States, and we shouldn’t tolerate it.”

Allen’s comments echo the message of former Secretary of Defense James Mattis, who said in a statement Wednesday that “we must reject any thinking of our cities as a ‘battlespace’ that our uniformed military is called upon to ‘dominate.”

“At home, we should use our military only when requested to do so, on very rare occasions, by state governors. Militarizing our response, as we witnessed in Washington, D.C., sets up a conflict—a false conflict—between the military and civilian society,” Mattis wrote.

Trump on Wednesday evening softened his tone around sending the military into American cities, saying, “I don’t think we’ll have to,” before reiterating that he has “very strong powers to do it” in an interview with his former press secretary Sean Spicer.

Still, Allen cast Trump’s threats as a dangerous tipping point for the country and urged the American people line up behind the message of George Floyd’s brother, Terrence, who called for peaceful protests in his brother’s name and urged people to vote.

“So, while June 1 could easily be confused with a day of shame and peril if we listen to Donald Trump, if instead we listen to Terrence Floyd, it is a day of hope. So mark your calendars—this could be the beginning of the change of American democracy not to illiberalism, but to enlightenment,” Allen wrote.

“But it will have to come from the bottom up. For at the White House, there is no one home.”