Ben Railton is a professor of English Studies and coordinator of American Studies at Fitchburg State University. He writes the daily AmericanStudies blog and his work has appeared in HuffPost, Talking Points Memo, the Washington Post and the Saturday Evening Post, where he is a columnist. His most recent book is "We the People: The 500-Year Battle Over Who Is American." The views expressed here are his. Read more opinion on CNN.

(CNN) Donald Trump's attack on four freshman Democratic congresswomen fits into a long tradition of people in power trying to define who is a real American—and an equally long tradition of resistance from those whom the powerful are trying to define out of the country.

Ben Railton

In his initial July 14th Twitter thread , Trump wrote that the congresswomen "come from countries whose governments are a complete and total catastrophe," and then suggested that they "go back and help fix the totally broken and crime infested places from which they came." Yet three of the four Congresswomen in question—Alexandria Ocasio-Cortez, Ayanna Pressley, and Rashida Tlaib—were born in the United States; only one, Ilhan Omar, was born in another country (Somalia) and arrived in the United States with her family nearly three decades ago at the age of 10.

While it's tempting to see this error as just another presidential misstatement or falsehood, I would argue instead that Trump's description of these four women and their distinct cultural and ethnic heritages—Puerto Rican, African-American, Palestinian, and Somali respectively—as all equally "coming from" outside of the United States is entirely purposeful, and indeed comprises a core element of his and his supporters' exclusionary vision of American identity.

As divisive and racist as the "send her back" gambit -- aimed at Rep. Omar and chanted fervently by Trump supporters at a recent rally -- is, Trump's use of it is far from unprecedented; it has a long and turbulent history that has helped shape our nation. In earlier moments in that history, as now, the movement to exclude has been met with, or intertwined with, efforts to promulgate an inclusive vision of this country.

My book reveals that such exclusionary definitions of America are but one side of a foundational and ongoing debate in the United States. These exclusionary visions define the American "we" by identifying numerous "thems" -- communities and cultures that are physically present in the United States but are not part of what this perspective sees as American identity. On the other side of this debate are definitions of the American "we" that see all those communities and cultures as instead integral parts of American identity.

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