If he assumes full power without institutional restraint, America could truly transform into a Fourth Reich: a great, ultra-nationalist, exclusive, and authoritarian power in the 21st century.
This rhetoric appeals to a conservative white voter base that feels threatened by globalization and the multicultural demographics of the US.
I don't think it is possible in the US because the two bold parts are in contradiction.
US is not a "natural" country, it is a colony and the ~350 million population are not Americans, they are immigrants who call themselves American. This is why they usually identify as Something-American like Irish-American, African-American, and so on. Something that is not true in a real country like Germany. Which is why "nationalism" has a different meaning too and could lead to "Reich" in Germany but not in the US.
Of course they have tried to artificially create the concept of "nationalism" in this colony by doing things like mass advertisement of benefits of "genetic/racial mixing" to strip the colonizers/immigrants of their ancestral identity and replace it with a new artificial one but their success rate is still small (30% IIRC) and the result is indifferent people who are more like potatoes rather than nationalists!
The main thing that used to unite all these completely different people under the same flag was the promise of "land of opportunity" something that was always a lie and is now long dead which is clear from Trump's main campaign ad/fake promise that won him the election: M.A.G.A.!
Trump's ultranationalist policies are indeed fundamentally at odds with America's multicultural demographic reality. However, it is precisely this contradiction that fuels Trump's politics, exploiting the fears of the long-dominant (white) group of losing its hegemonic position. Ultimately, America has always been at a crossroads between closing itself off to exclusive nationalism or embracing pluralism as its global strength.
The history of the United States has not been smooth since its inception, but rather marked by a perpetual struggle between inclusivity and exclusivity. In the 19th century, large waves of immigration from Ireland and Germany gave rise to the Know-Nothing Party political movement, which rejected Catholics and poor immigrants. In 1882, the Chinese Exclusion Act was passed, explicitly banning Chinese immigration—one of the most blatant forms of racial discrimination in American legal history.
In the early 20th century, waves of immigrants from Southern and Eastern Europe were also perceived as a threat. The government implemented a strict quota system based on country of origin, demonstrating that "America's door" was not always open to all. However, a turning point came in 1965, when the Immigration and Nationality Act was enacted. This law abolished the racial quota system and opened the door to immigrants from Asia, Latin America, and Africa. From this, America developed into the multicultural nation we know today. In other words, the narrative of "America as a land of immigrants" is not a linear journey, but rather a cyclical push and pull between political nativism and the spirit of pluralism.
In the contemporary political landscape, Trump has emerged as a symbol of the rise of populist ultranationalism. Through the slogans "Make America Great Again" and "America First," he has echoed rhetoric emphasizing economic protectionism, immigration restrictions, and a rejection of globalism, which he considers detrimental to the American people, as exemplified by the Mexican border wall, the Muslim ban, and anti-China rhetoric. These policies stem from Trump's political base: the white lower-middle class living in rural and industrial areas. This group feels displaced by globalization, losing manufacturing jobs, and experiencing an identity crisis due to demographic change. Trump offers an exclusive nostalgia, a picture of an old America that was homogeneous, predominantly white, and centered on conservative Anglo-Saxon Protestant values. But here's the paradox: America's current social reality is moving in the opposite direction.
A fundamental contradiction is clearly visible here. Trumpism (which seeks to restore mono-ethnic dominance and nativist rhetoric) is actually colliding with the inevitable currents of history: America is a multicultural nation and will become even more so. The American Dream, the inclusive narrative that anyone, regardless of origin, can succeed through hard work, is a fundamental principle. Diversity is not just a social reality, but also a strategic resource that makes America competitive globally.
This contradiction is not just a matter of electoral politics, but also of national identity. If ultranationalism prevails, America will lose its global image as a nation of immigrants and a champion of liberal democracy. If multiculturalism prevails, America will retain its appeal as a magnet for global talent and innovation.
Looking ahead, political polarization between conservative nationalists and liberal multiculturalists will intensify, and the potential for social conflict will increase, particularly on issues of race, religion, and economic class. American democracy will be tested by internal divisions.
When ultranationalism dominates, America's soft power weakens. The world no longer sees the US as a land of hope, but as a bastion of exclusivity. On the other hand, even as pluralism strengthens, America remains a center of innovation, education, and cultural power that captivates the world.