Republican presidential hopeful Donald Trump speaks during a brief stop at a campaign event in Laredo, Texas, Thursday, July 23, 2015. (AP Photo/Darren Abate)

This opinion piece is by Cardinal Timothy Dolan, archbishop of the New York Archdiocese.

During those happy days decades ago when I taught American religious history to university students, I spent a chunk of time in class on the ugly phenomenon called nativism, defined by the scholar and author Ray Allen Billington as, “organized, white, Protestant antagonism toward the Catholic immigrant.”

It flourished in our country during the 1840s and 1850s — actually becoming a popular political party, the Know-Nothings — and appeared again, in the 1870s, as the American Protective Association; in the 1920s, as the KKK; and during post-World War II America, as Protestants and Other Americans United for Separation of Church and State.

These nativists believed the immigrant to be dangerous, and that America was better off without them. All these poor degenerates did, according to the nativists, was to dilute the clean, virtuous, upright citizenry of God-fearing true Americans.

(Among other American minorities, it must be said, Catholics like me often drew the ire of nativists.)

I made the point to my students that nativism never really did disappear completely, but was a continual virulent strain in the American psyche, which would probably sadly show up again.

This point my students would not buy. “Father Dolan,” they would say, “there’s no denying that this bigotry was there in our past. But, come on! Who could ever believe now that immigrants are dirty, drunken, irresponsible, dangerous threats to clean, white, Protestant, Anglo-Saxon America! Those days are gone.”

I wish I were in the college classroom again, so I could roll out my “Trump card” to show the students that I was right. Nativism is alive, well — and apparently popular!

American historians describe two approaches to the immigrant. One is, sadly, the nativists, who see the unwashed, ignorant, bothersome brood as criminals and misfits who threaten “pure America,” and are toxic to everything decent in the United States. As journalism professor Paul Moses writes, this group believed that “American society was doomed, as the foundation stone of Plymouth Rock eroded with the crash of each immigrant wave.”

The second is the more enlightened and patriotic view. This approach sees the immigrant as a gift to our nation, realizing that the only citizens whose ancestors were not immigrants are the Native Americans. All of us here are descendants of newcomers.

Yes, this second group claims, we need to control our borders, fairly regulate immigration and be prudent in our policies and laws, but we are wise to consider the immigrant as good for our beloved nation. To welcome them is virtuous, patriotic and beneficial for the economic and cultural future of our country.

I am not in the business of telling people what candidates they should support or who deserves their vote. But as a Catholic, I take seriously the Bible’s teaching that we are to welcome the stranger, one of the most frequently mentioned moral imperatives in both the Old and New Testament.

As an American, I take equally seriously the great invitation and promise of Lady Liberty. It’s one of the reasons why I am so eager to share with Pope Francis the wonderful work being done by our Catholic Charities to assist immigrants who come to New York, and look to the church for assistance and a warm welcome. I guess, as a Catholic American, I’m a bit biased. Walt Whitman called my predecessor Archbishop John Hughes a “mitred hypocrite,” because the prelate defended his poor Irish immigrant flock — the Mexicans of his day — from the nativists. The same Whitman called the immigrants “these dregs of foreign filth, refuse of convents, scullions from monasteries . . .”

Thank God Walt Whitman stuck to poetry, and did not run for President.

This piece first ran in the New York Daily News.

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