Donald Trump has been saying that Ted Cruz can't be president because he was born in Canada, and the U.S. Constitution limits eligibility to natural born citizens. I thought at first that Trump was just slinging mud because Cruz had pulled ahead in the Iowa polls. But it fits too well with what is becoming a leitmotif of the Republican primaries.

The point of the "natural born citizen" clause, according to Justice Joseph Story's famous "Commentaries on the Constitution," was to keep "ambitious foreigners" from "intriguing for the office." This concern about the patriotism of immigrants found statutory expression in the Alien and Sedition Acts of 1798.

Those four laws, enacted in the final years of John Adams' administration, extended the residency requirement for citizenship from 5 to 14 years; they allowed the president to deport aliens deemed dangerous, and they made it a crime to make false statements critical of the government. Adams' Federalist Party was worried about importing ideas from the French Revolution.

The Alien and Sedition Acts of 1798 codified an American suspicion about the loyalty of aliens. There was, however, another side to the debate. Thomas Jefferson was a Francophile. His Democratic-Republican Party was more welcoming to immigrants. And his party won the election of 1800.

We are seeing a rebirth of the suspicion of immigrants in this year's Republican primary debates. For years, we have had a simmering disagreement about immigration from Latin America. This has been about jobs, social costs (schools, health care), language, culture, sovereignty and respect for the rule of law.

But now it has gotten mashed together with national security. We worry about a repeat of Sept. 11, this time with ISIS rather than al-Qaida as the perpetrator. We have an attack by Islamic extremists in San Bernardino, a policeman shot in Philadelphia. We hear about sexual assaults in Cologne, Germany. Europeans worry that they have imported an alien view that demeans women; Americans don't want that either.

And Trump says that Cruz can't be president because he is not the right kind of citizen. It all fits. But I really don't like it.

"You shall not oppress a resident alien," Exodus 23:9 exhorted the people of Israel, "you well know how it feels to be an alien, since you were once aliens yourselves in the land of Egypt." This Old Testament commandment is conspicuously unlike the more famous "eye for an eye."

God did not tell the Israelites to treat others badly because that's how the Egyptians treated them. He told them to treat others better than they had been treated.

In Matthew 7:12, Jesus offered an even broader exhortation to charity in all matters. "Do to others whatever you would have them do to you."

Catholics should be especially sensitive to this injunction when it comes to immigration policy. Americans of the 19th century worried about the Irish and the Italians, because (it was said) that their loyalty to the pope would make them untrustworthy citizens.

Passions over the immigration issue are strong, and the fears behind them cannot simply be dismissed as frivolous because they are not. But those who have been entranced by Trump, his casual disparagement of Mexicans and his desire to exclude all Muslims from America need to open their minds and hearts.

The same kind of attractive and simplistic, easy-answer thinking motivated Adams to sign the Alien and Sedition Acts, which he would later consider his greatest mistake.

Not only was his answer to a foreign threat morally and constitutionally suspect, but it's worth remembering that Jefferson went on to beat him. There's a lesson there for today's Republicans, if they ever hope to govern.



- Garvey is president of The Catholic University of America in Washington, D.C.