Immediately, there were numerous protests and legal challenges, with some calling it a "Muslim ban" due to the fact that six of the affected countries had a Muslim majority. A nationwide temporary restraining order (TRO) was issued on 3 February 2017 in the case Washington v. Trump, which was upheld by the United States Court of Appeals for the Ninth Circuit on 9 February 2017. Consequently, the Department of Homeland Security (DHS) stopped enforcing portions of the order and the State Department re-validated visas that had been previously revoked. The order was criticized by members of Congress from both parties, universities, business leaders, Catholic bishops, top United Nations officials, a group of 40 Nobel laureates, Jewish organizations, 1,000 U.S. diplomats who signed a dissent cable, thousands of academics, and longstanding U.S. allies.
Key provisions of executive orders 13769 and 13780 cite to paragraph (f) of Title 8 of the United States Code § 1182, which discusses inadmissible aliens. Paragraph (f) states:
The act that underlies this, known as the Immigration and Nationality Act of 1952 (a.k.a. the McCarran–Walter Act), was amended by the Immigration and Nationality Act of 1965 (a.k.a. the Hart−Celler Act), which included a provision stating
The language in the INA of 1965 is among the reasons District of Maryland Judge Chuang issued a temporary restraining order blocking Section 2(c) of Executive Order 13780.
In 1986, the Visa Waiver Program was initiated by President Ronald Reagan, allowing alien nationals of select countries to travel to the United States for up to 90 days without a visa, in return for reciprocal treatment of U.S. nationals. By 2016, the program had been extended to 38 countries. In 2015, Congress passed a Consolidated Appropriations Act to fund the government, and Obama signed the bill into law. The Visa Waiver Program Improvement and Terrorist Travel Prevention Act of 2015, which was previously passed by the House of Representatives as H.R. 158, was incorporated into the Consolidated Appropriations Act as Division O, Title II, Section 203. The Trump administration's executive order relied on H.R. 158, as enacted. The Visa Waiver Program Improvement and Terrorist Travel Prevention Act originally affected four countries: Iraq, Syria, and countries on the State Sponsors of Terrorism list (Iran and Sudan). Foreigners who were nationals of those countries, or who had visited those countries since 2011, were required to obtain a visa to enter the United States, even if they were nationals or dual-nationals of the 38 countries participating in the Visa Waiver Program. Libya, Yemen, and Somalia were added later as "countries of concern" by Secretary of Homeland Security Jeh Johnson during the Obama administration. The executive order refers to these countries as "countries designated pursuant to Division O, Title II, Section 203 of the 2016 consolidated Appropriations Act". Prior to this, in 2011, additional background checks were imposed on the nationals of Iraq.