When Richard Spencer, a leading alt-right white power ideologue finished his speech at Saturday’s day-long “Become Who We Are” summit at Washington’s Ronald Reagan Building, someone yelled, “Heil the people!” and the room shouted back, “Heil victory!”

It wasn’t the evening’s first Nazi reference, nor most brazen. Soon after Spencer started slamming the mainstream media, overlooking how they gave the president-elect endless free coverage, he jeered, “Perhaps we should refer to them in the original German?” The crowd shouted back, “LÃ¼genpresse,” a Nazi-era word for “lying press.” Spencer said, to cheers, that white power was rising. “America was, until this last generation, a white country designed for ourselves and our posterity… It is our creation, it is our inheritance, and it belongs to us.”

America under Donald Trump is entering an uncharted authoritarian era. Whether apt historical precedents are in the first months of Hitler’s rule in 1933 in Germany or closer to the 1950s anti-Communist witch hunts led by Sen. Joseph McCarthy, remains to be seen. But there are myriad events everyone is seeing and unfolding behind closed doors that are forming a prologue to Trump’s authoritarian rule.

Looking backward, people always ask if the course of history could have been changed. Many people would like to dismiss some of the recent events as bad dreams that will vanish if ignored, like last weekend’s neo-Nazi rally in a federal office complex in the capitol; like Trump taking to Twitter to denounce the cast of the musical, Hamilton, for openly imploring Vice-President-elect Mike Pence, who was in attendance, to honor America’s diversity.

But that becomes harder to do when the president-elect is appointing scarily intolerant propagandists and warmongers to top White House posts. It looks like Trump is posed to deport millions of migrants, roll back civil rights and go after his critics, by appointing race-baiting propagandist Steve Bannon as a top adviser; Alabama Sen. Jeff Sessions as Attorney General; and Lt. Gen. Michael Flynn as top national security adviser, a man who supports racial profiling and repeats the lie that Islamic law is spreading across America. Trump seems to be relishing his unfolding role as an American strongman, as evidenced by his Sunday tweet: “General James 'Mad Dog' Mattis, who is being considered for Secretary of Defense, was very impressive yesterday. A true General's General!”

The question is how far Trump will go to achieve his objectives at home and abroad, including putting the country on a path toward war. Historic comparisons are both useful and imprecise. Yet there are enough echoes of Germany in 1933, the year Adolf Hitler became the country’s newly appointed chancellor. Then and now were periods seen by some as a brutal darkening and others as a great national revival. (My most recent book is set in Holland during the war.)

As with Hitler’s earliest days in power, we are seeing an increase in race-based hate crimes. Back then, the targets were communists, socialists and Jews. Today the targets are Muslims. Trump’s advisers are pointing to a much-criticized World War II-era Supreme Court ruling, Korematsu v. United States, which held that wartime detention was constitutional, to allow creation of a national Muslim registry.

Where today parts with the past, at least so far, is that we haven’t seen how Trump would expand the federal policing and deportation apparatus. People forget that President Obama oversaw the arrest and deportation of 2 million immigrants before signing executive orders suspending deportation of 40 percent of the 11 million undocumented migrants here. It’s an open question what Trump would do to accelerate the federal police state. In Germany, Nazi-supporting paramilitary groups created their own arrest, detention and torture stations during the first year of Hitler’s rule. The authorities didn’t stop them, and most of the American journalists stationed there at the time didn’t want to conclude that paramilitary violence was part of a larger societal trend.

What the people outside targeted circles in Germany didn’t want to see at the time were the steps being taken to start transforming a democratic republic to authoritarian rule. (The military buildup and dictatorship followed.) In short, the telltale signs were the increasing control the government exerted over all aspects of society, but especially the civil rights of the officially loathed minorities. It started with national registries, moved to what jobs they could and could not hold, and then declaring and forfeiting property and assets.

What is the contemporary parallel? On immigration, visa-less detainees have virtually no legal rights. Until Obama issued his executive orders suspending deportations in his second term, undocumented people arrested for traffic stops would be turned over by local police to ICE—federal immigration authorities—and disappear into a deportation treadmill. Trump and the GOP have threatened to ramp up that process, including the prospect of blocking all federal aid to any municipality or state that acts as a sanctuary state. There’s also been talk about seizing the international wire transfers of money migrants send to their families in Mexico and Central America. What’s clear is that this is uncharted territory, domestically speaking.

What happens with the Muslim registry, segments of police forces resurrecting racial profiling, crackdowns against protesters and dissent, are all open questions. But the president-elect and his top advisers, like most of the anti-communist crusaders of the 1950s McCarthy era, have shown little tolerance for dissent and a willingness to go after their critics. In California, people at anti-Trump protests talk about opening their homes to people fleeing federal police sweeps. The last time that was heard was in the 1980s when refugees fled Ronald Reagan’s Central American wars and hid from U.S. authorities here.

During the first months of Hitler’s rule, German authorities told foreign journalists and diplomats that attacks by fascist thugs were outliers and would soon end. There were even official denunciations by the government, but the attacks didn’t stop. A handful of Americans were even assaulted, after being in the wrong place at the wrong time. But most of the foreign press corps, visiting tourists and even diplomats didn’t grasp the emerging character of the new regime. And those who did see it for what it was—after witnessing violence firsthand—and tried to talk about it, were frequently dismissed as too political, prejudiced and shrill.

Some people may shrug and say that upheaval and random victims always accompany every revolution—including what’s in store as Trump strives to “make America great again.” Others may respond that people must speak out against dark forces when the future hangs in a balance and those accumulating power are silently gathering their forces. What’s certain about Trump’s America is the country is heading into an authoritarian time. How wide, how deep and how destructive that wave will be is unknown.

As Richard Spencer, who led the neo-Nazi chants last weekend at the white power gathering in Washington told the New York Times, his movement and Trump share many values. “I do think we have a psychic connection, or you can say a deeper connection, with Donald Trump in a way that we simply do not have with most Republicans.”