In a later iteration, therefore, Trump said he would ban immigration from countries with a track record of terrorism. Trump more or less admitted this was a sham: “People were so upset when I used the word ‘Muslim.’ ‘Oh, you can’t use the word “Muslim.”’ Remember this. And I’m OK with that, because I’m talking territory instead of Muslim.” The switch circumvented the religious test, but raised other problems. For example, would it prevent immigration of people from Britain, France, or Belgium, countries that have grappled with a series of terrorist attacks? Trump was vague. At one point, he said that Muslims from Britain would be acceptable.

Meanwhile, the territory-based idea created other problems. The plight of Christians in the Middle East, who have been persecuted by ISIS, al-Qaeda-linked groups, and others, is a popular cause with Christians in the United States, particularly the conservative ones who form an important part of the Republican base. The plight of Jews in Muslim countries is also a treasured cause. That created a bind for Trump’s running mate Mike Pence, as my colleague Emma Green reported. Pence needed to defend Trump’s policy without appearing to be abandoning persecuted Christians. A Pence spokesman later said that he would support the creation of “safe havens” where Christians and Jews could be protected while being vetted.

The idea of safe havens for refugees is not new, but it has proven tricky to implement. It is either extremely costly and logistically challenging, or else it tends toward failure and tragedy, as occurred with inadequately protected UN “safe areas” in Bosnia during the 1990s.

Trump’s latest idea is to focus on individuals themselves. The AP reports that those seeking to enter the U.S. would be queried on their stances on issues like religious freedom, gender equality and gay rights: “Through questionnaires, searching social media, interviewing friends and family or other means, applicants would be vetted to see whether they support American values like tolerance and pluralism.”

He was somewhat more vague in the speech itself:

In the Cold War, we had an ideological screening test. The time is overdue to develop a new screening test for the threats we face today. In addition to screening out all members or sympathizers of terrorist groups, we must also screen out any who have hostile attitudes towards our country or its principles—or who believe that Sharia law should supplant American law. Those who do not believe in our Constitution, or who support bigotry and hatred, will not be admitted for immigration into the country. Only those who we expect to flourish in our country—and to embrace a tolerant American society—should be issued visas.

It’s an interesting approach, not least in the items Trump’s advisers have named as criteria. Trump has struggled to support religious freedom, not least with his initial Muslim immigration proposal. He has struggled with tolerance more broadly, for example offering a highly dubious definition of free speech and calling for stricter libel laws. Trump might be in the position of demanding that those seeking to immigrate to or seek refuge in the United States uphold values that he himself seems ambivalent about.