People familiar with the immigration system say that many of Donald Trump's ideas will be nearly impossible to implement. | AP Photo Why Trump's immigration ideas won't work The Republican nominee's proposals appear nearly impossible to implement — and critics say they could actually fuel the terrorist threat.

Donald Trump on Monday laid out some big plans to change the U.S. immigration system, calling for the suspension of immigration from regions that have "a history of exporting terrorism" and the roll-out of an ideological test to weed out foreigners who may support "radical Islamic terrorism."

The problem, people familiar with the immigration system say, is that many of Trump's ideas will be nearly impossible to implement. And some may wind up actually increasing the terrorist threat.


The Republican presidential nominee unveiled the proposals during a speech in Ohio on national security. "We should only admit into this country those who share our values and respect our people. I call it extreme vetting," the real estate mogul said, ad-libbing the "extreme vetting" line. "Those who do not believe in our Constitution, or who support bigotry and hatred, will not be admitted for immigration into the country."

Critics argue that Trump's plans are just a way to bar Muslims from the U.S., an idea he suggested months ago but which even some Republicans called an "un-American" religious test. (Trump also wants a ban on Syrian refugees.) Regardless of his true intentions, the basics that Trump proposed Monday left observers struggling to envision how they could ever become a reality.

For instance, some asked, what does Trump mean by "terrorism" and "regions" with "a history of exporting terrorism?" Who counts as an immigrant — people who want to move to the U.S. permanently or the many millions who come as tourists, often without a visa? What counts as "bigotry and hatred?" And how will the ideological test be administered?

Trump's proposals now are "no more specific than saying you’re going to screen out Muslims — it’s less specific than that. In a way he’s made his proposal less narrow and even vaguer than it was before," said David Bier, an immigration analyst at the libertarian Cato Institute. "Vague proposals rarely get implemented in any sort of specific, targeted way."

Trump's team has promised more details in the coming weeks. As they figure them out, they'll face some tough realities.

For one thing, there are few regions in the world not affected at some point by some form of terrorism. In Europe alone, Spain has suffered from attacks by Basque separatists the U.S. labels as terrorists, while Northern Ireland is still troubled by offshoots of the Irish Republican Army. Even if Trump were to focus purely on Islamist-inspired terror, that would still presumably include much of Europe, including France and Britain, most of whose citizens currently enjoy visa-free tourist travel to America.

"Are we calling for restrictions on visas to countries that have some of the best criminal justice and international policing programs?" asked Greg Chen, a top official with the American Immigration Lawyers Association, in reference to Western European states.

Then there's the Middle East, which is deeply scarred by terrorism but includes countries such as Jordan, Egypt and Israel, whose governments are important partners in the fight against Islamist extremists. Trump actually singled out those three countries in his speech, calling them friends "who recognize this ideology of death that must be extinguished." But those countries — not to mention others — may resent seeing their citizens barred by the U.S. That could affect their cooperation on fighting extremists just as the U.S. is making headway in the fight against the Islamic State terrorist group in Syria and Iraq.

"Freedom of travel, whether regulated by visa or not, to the United States is a critical element of our relationship with these countries. It’s a matter of dignity," said Jeremy Shapiro, director of research at the European Council on Foreign Relations.

Trump also kept using the word "region," but the U.S. immigration and visa policies are largely built around country-to-country relationships, and some countries don't clearly fall into one region or another: Turkey, for example, is a country that straddles Europe and the Middle East.

U.S. immigration policy is incredibly complex and it is often affected by political decisions that seem questionable. For instance, earlier this year, the Obama administration imposed special visa restrictions on foreigners who have traveled in recent years to Iran, Iraq, Syria, Sudan, Libya, Somalia and Yemen. But the administration chose not to include on that list Saudi Arabia or Pakistan, two countries notorious for producing terrorists, because the governments in Riyadh and Islamabad are, technically, allies in the fight against extremism.

The U.S. government has very broad authority when it comes to deciding which foreigners it allows on its soil, and it does occasionally bar people, such as foreign government officials believed to be human rights violators. Historically, the U.S. also has barred people based on their beliefs, including in communism, a Cold War approach Trump alluded to in his speech. Legislative changes have made such ideological bans less likely today, but the rules are not black and white. Some experts assert that even if a Trump administration were to try to bar people based on their religion it may not technically be unconstitutional, even if it would seem to violate the spirit of the First Amendment.

Constitutionality aside, the ideological test proposed by Trump poses challenges on a sheer logistical level, and could cost huge amounts of money to implement. Would the test come in the form of a questionnaire? Interviews with consular officers? The deployment of people to scour immigration applicants' social media accounts?

And what counts as an un-American value?

In his speech, Trump castigated radical Islamists for their hatred of gays, but would he argue that evangelical Christians from South Korea who also denounce homosexuality should be barred from visiting the United States?

"Immigration to the United States would grind to a near halt if millions of people are subject to background checks based on subjective criteria," said Cornell University law professor Stephen Yale-Loehr, who added: "This proposal would also cost billions of dollars to implement. Business people and visitors could not be able to plan quick trips to the United States because they would not know how long an ideological background check would take."

Trump on Monday also slammed Democratic presidential nominee Hillary Clinton for saying in the past that she wanted to see more Syrian refugees be allowed in the United States, warning that terrorists and criminals are hiding among the refugees (though Clinton has said refugees must be carefully vetted). But refugee advocates warn that Trump's comments only worsen America's reputation in the Middle East, spurring more young people to turn to Islamist extremism.

Hina Shamsi, director of the National Security Project at the American Civil Liberties Union, said that, despite the change in language, Trump's overall goal appears to still be keeping out Muslims. She believes that would be unconstitutional. “It’s hard to see how these proposals do not pose significant legal, policy and practical hurdles, and rightly so,” she said.