Since 2016, the visa waiver no longer applies in cases where a person travelled to Iran, Iraq, Libya, North Korea, Somalia, Sudan, Syria or Yemen on or after 1 March 2011 or to persons with dual Iranian, Iraqi, Sudanese or Syrian nationality.  Certain categories such as diplomats, military, journalists, humanitarian workers or legitimate businessmen may be required to be required to be required to be bound by the Secretary of Homeland Security.  On June 17, 2008, Bulgarian Foreign Minister Ivailo Kalfin and US Secretary of Homeland Security Michael Chertoff signed an interim agreement under the Visa Waiver Program, the press service of the Bulgarian Foreign Ministry said in a statement.  All arriving passengers who intend to use the Visa Waiver Program when travelling to the United States. by air or sea are required to apply for a travel authorization via the online Electronic System for Travel Authorization (ESTA) prior to departure for the United States, preferably at least 72 hours (3 days) in advance. This new requirement was announced on June 3, 2008 and is intended to enhance U.S. security by screening passengers participating in the VWP before screening terrorist and/or no-fly lists and databases. The electronic authorization, valid for a period of two years, reflects the Australian system of the Electronic Travel Authority. Approval is mandatory for participating VWP citizens before embarking in the U.S., but as with formal visas, this does not guarantee entry into the U.S. as final eligibility at U.S.
ports of entry is determined by CBP officials. Following the enlargement of the European Union in 2004, newly admitted countries and EU agencies began to lobby intensively to include these new countries in the VWP. The U.S. government first responded to these efforts by developing bilateral strategies with 19 candidate countries, known as the Visa Waiver Roadmap Process.   The U.S. government began to accept the possibility of departing from the original criteria for designating the country – which were in itself included in the Immigration Act – and adding political criteria, the latter of which may prevail over the former. This development began with Bill S.2844, which explicitly identified Poland as the only country to be added to the VWP, and continued as an amendment to the 2006 Comprehensive Immigration Reform Act (p. 2611), whose Sec. 413, Visa Waiver Program Expansion, set out more comprehensive criteria that would apply to any EU country that “materially supported” multinational forces in Iraq and in Afghanistan. However, the definition of this “material support” would again be respected only by Poland and Romania, a fact that was not welcomed by the other candidate countries for EU membership.