The travel ban is back. It’s permanent. It hits a number of America’s counterterror partners. And its rationale is—at least partially—an official secret.

The White House announced on Sunday evening that President Donald Trump has implemented strict new limitations on which people from a few troubled countries can visit America—including countries that the president himself acknowledges are valuable partners to the U.S. in efforts to combat terrorism.

The United States now has dramatic limitations on which nationals from eight countries—Chad, Iran, Libya, North Korea, Somalia, Syria, Venezuela, and Yemen—can travel here. The limits are slightly different for each of those countries, and they’re indefinite; unlike the first travel ban, which was only in place for a few months, this one has no stated end date.

The United States has a significant military presence in some of the banned countries. The U.S. is essentially waging a proxy war in Yemen, it’s at loggerheads with Iran—a tension the president eagerly highlighted in his UN speech last week—and it has Special Operations forces on the ground in Somalia, Syria, and Libya. During the Obama administration, the U.S. also had a small military presence in Chad and considered it a hub for military activities in Africa.

Despite the assistance these countries’ governments have provided to the U.S.—and despite the presence of American troops on their soil—they are singled out under the ban.

The proclamation specifically says the U.S. government “looks forward to expanding” its cooperation with Chad, Libya, and Yemen. It’s pretty safe to guess that the new travel ban won’t make those countries any more eager to expand their partnerships with the American government.

The new rules are slightly different for each country.

In the proclamation the president signed implementing the new travel ban, he cited a report from Acting Homeland Security Secretary Elaine Duke as saying the countries have policies that threaten “the security and welfare of the United States.”

The proclamation also expresses a generalized fear of immigrants.

“Lawful permanent residents are more difficult to remove than nonimmigrants even after national security concerns arise,” it reads, “which heightens the costs and dangers of errors associated with admitting such individuals.”

And it specifically states that it doesn’t give Americans all the reasons for the travel bans. Though it gives short rationales for the travel limits on each country, it also specifically states that those explanations are incomplete.

“Describing all of those reasons publicly, however, would cause serious damage to the national security of the United States, and many such descriptions are classified,” the proclamation says.

The proclamation bans immigration to the U.S. by people from seven of the eight countries (all but Venezuela)—meaning nationals of those countries can no longer obtain lawful permanent residence and become eligible for Green Cards and citizenship.

Unlike the president’s first travel ban, this one doesn’t have an expiration date. Instead, it requires the Homeland Security secretary, the attorney general, the secretary of State, and the director of national intelligence to submit a report to the White House every 180 days recommending whether or not the ban should stay in place as is.

The proclamation lays out a host of exceptions and waiver qualifications, including for people who work with the United States government, for diplomats, and for people who have “significant contacts with the United States.” A few North Koreans come to the U.S. every year for UN purposes, and they presumably won’t be impacted by the ban.

Trita Parsi—who heads the National Iranian American Council, which backs warmer relations between Washington and Tehran—told The Daily Beast the travel ban undercuts Trump’s comments to the United Nations last week. The president and the State Department frequently say that the United States’ criticism is with the Iranian government, and not its people. But this ban, with its carve-out for diplomats, is decidedly focused on the people of Iran. Parsi said that will be clear to Iranians.

“You cannot assume them to be so stupid that they will not understand,” he said.