For over 100 years (at least)
American Presidents have (overtly) governed by appealing to a united United States of America. They talked about the strength of the American people, of the resourcefulness of the American people, even of the goodness of the American people. They talked about common beliefs, about there being much more that united us than divided us. I have personal memories of 11 of them (I was a toddler during Truman). They all at least tried to project at least a veneer of bipartisanship and inclusiveness while they claimed to represent all Americans
Often they only invoked the myth of America, the one in which all people are treated equally. But very very rarely did they openly work to divide us even further than we already were. Nixon came closest to openly playing "us" against "them". But then the divisions among us were already exploding all around us anyway - with racial disturbances and anti-war protests engulfing large swathes of our nation. And even Nixon did not stake out the divisive extreme; George Wallace was the national figure doing that.
We do not need to invoke comparisons to a certain German leader of a former century, he was not alone in his play book, just in how far he took it. There are many rulers who consolidate power by pitting the majority of their citizens against delegated scapegoat minorities, while deriding all open opposition to their policies as anti-patriotic - even to the point of calling critics "enemies of the people". They just, until now, have not been American leaders.
This is what defines the Trump presidency; broad brush smear campaigns against any group not his own, against any organized entity that chooses to oppose him. He intentionally uses his "bully pulpit" to inflame divisions, not to heal them. He openly mocks his "fellow Americans" for daring to differ from him. History has shown that, hideous though it is, that path can lead the consolidation of state power in the hands of those who are willing to promulgate the most hideous of lies.
This is why Donald Trump is an American fascist, though his stated ideology and actions to date may still seem, to many, to fall short of that creed.
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