In a conference call with reporters on Monday, Homeland Security officials stressed the order’s narrow impact. “If you're in the United States on the effective date of this order, which is March 16, it does not apply to you,” a senior Homeland Security department official said. “If you have a valid visa on the effective date of this order, it does not apply to you.” Travelers from the six countries with valid, multi-entry visas “aren’t going to have any issues,” the official emphasized.

Another major change is the removal of Iraq from the list of countries affected by the moratorium. “On the basis of negotiations that have taken place between the Government of Iraq and the U.S. Department of State in the last month, Iraq will increase cooperation with the U.S. Government on the vetting of its citizens applying for a visa to travel to the United States,” the Department of Homeland Security said in a factsheet on Monday. “As a result of this increased information sharing, Iraqi citizens are not affected by the Executive Order.”

That change came amid strong diplomatic pressure from the Iraqi government, which is currently fighting alongside the U.S. military against ISIS in the country’s northern regions. Iraqi translators who worked alongside U.S. soldiers during the war will also be free to enter the United States; their exclusion from the original order frustrated Pentagon officials until the Trump administration carved out an exemption in February.

In addition, the new order includes a series of exemptions that U.S. immigration officials can use to waive the six-nation visa ban on a case-by-case basis. Those provisions allow officials to issue visas to student and work visa-holders outside the country when the order goes into effect, infants and children, people needing urgent medical care, U.S. government employees, members of certain international organizations, and immigrants to Canada.

Like its predecessor, the new order also shuts down the U.S. Refugee Admissions Program for 120 days, effectively halting the admission of new refugees into the United States for four months. But Monday’s order no longer includes the January 27 order’s permanent ban on Syrian refugee admissions, and it also removes the exemption for religious minorities.

The genesis of Trump’s executive order dates back to his December 7, 2015 call for a “total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on.” Over the course of the presidential campaign, the “total and complete shutdown” shifted towards calls for “extreme vetting,” which, as my colleague David Graham noted, sounded a lot like the current vetting system in place for refugees and immigrants.

Most of the changes seemed designed to insulate the order from a defeat in the courts, and U.S. officials framed it as a valid national-security measure. “This is not a Muslim ban in any way, shape, or form,” a senior Department of Homeland Security official said during the Monday conference call. “This is temporary suspension from six countries that are either failed states or state sponsors of terror.”