Spicer noted that the seven counties put on the list were chosen by the Obama administration. Indeed, it has its roots in the visa-waiver program. The U.S. allows the citizens of more than 30 countries to visit for short stays without a visa under this program. But that visa waiver does not apply if a citizen of an eligible country has visited—with some exceptions—Iran, Iraq, Libya, Somalia, Sudan, Syria, or Yemen on or after March 1, 2011—under measures put in place by the Obama administration. Those individuals must apply for a visa at a U.S. consulate. These seven countries are listed under section 217(a)(12) of the INA, 8 U.S.C. 1187(a)(12) of the U.S. code, and it is this code that Trump’s executive order cited while banning citizens of those nations.

What is the impact?

The number of permanent residents from these countries is relatively small. For instance, 1,016,518 green cards were issued in 2014. Of these, 19,153 went to Iraqis and 11,615 to Iranians, according to the Department of Homeland Security’s data. These two countries make up the overwhelming majority of U.S. permanent residents from among the seven nations, which together have 500,000 permanent resident in the U.S., according to ProPublica. But the seven nations, as I reported this week, also account for 40 percent of U.S. refugee intake.

Trump himself seemed to dismiss the impact, tweeting Monday: “Only 109 people out of 325,000 were detained and held for questioning.”

Numbers, however, seldom tell the whole story. There have been multiple reports since the executive order was signed of people being prevented from boarding flights; refugees, who had gone through the years-long process before being approved to come to the U.S., stranded in third countries; of Iraqis who had worked for years with the U.S. military being denied entry; of Iranian students stuck overseas; of U.S. tech companies recalling its foreign workers because of the possible impact. And there have been protests against the order at airports across the country, including at New York’s JFK International Airport and Dulles Airport outside Washington, D.C. , and the Los Angeles International Airport where lawyers, demonstrators, and the media descended to witness the order’s impact.

Is this a Muslim ban?

Technically, no. The ban includes seven majority Muslim countries, but by no means are these states the most populous Muslim countries, nor are they among the top sources of Muslim immigration to the U.S., nor have they produced terrorists in the same numbers as other Muslim countries not on the list. Indeed, Muslims from Saudi Arabia, Egypt, Pakistan, and other countries can still visit the U.S.

Still, advocacy groups challenging the order say a Muslim ban is precisely what it amounts to. Indeed, they cited former the words New York City Mayor Rudy Giuliani’s comments Saturday on Fox News. Giuliani said that Trump had asked for a “Muslim ban,” but one that was done legally. He said he and a panel of experts “focused on, instead of religion, danger.”