The Visa Waiver Program
The Visa Waiver Program (VWP) was implemented by the Department of Homeland Security for the purpose of allowing certain nationalities easier access to the United States of America. The VWP offers travelers going to the US the possibility to apply for an ESTA travel permit, dropping the need to apply for a visa. The ESTA application procedure is faster, easier, and cheaper than a visa application for gaining access to the US.
The Visa Waiver Program and the ESTA
The requirement to apply for an ESTA before leaving for the United States was implemented in 2009. The Visa Waiver Program exists since 1986. Until 2009, checking of passengers under the Visa Waiver Program happened through the green I-94W form. This form was handed out on flights to the United States. On arrival in the USA, the customs clerk would check the passengers and their I-94W form.
The terrorist attacks on the World Trade Center were the cause to change the checking from the moment of arrival to the moment before departure. After all, the terrorists had shown that damage could be done before passing through customs. Following September 11 2001, the 9/11 Commission Act was implemented. This requires an individual check of all travelers to the US, before they are allowed to board a plane or boat headed for the US. Because applying for a visa is a relatively extensive procedure, the US Department of Homeland Security decided to introduce a new and automated system; the ESTA (Electronic System for Travel Authorization). Because an ESTA traveler permit can be acquired online the impact of this safety check is limited.
Permission and provision
Permitting travelers to the United States under the Visa Waiver Program consists of two checks; one automated check before departure and a manual one on arrival.
First check: before departure
Firstly, travelers need to possess an ESTA acquired under the Visa Waiver Program, a US visa or an American passport. The Department of Homeland Security has agreements with virtually all airlines with flights to the US. A part of this agreement is checking passengers for a valid ESTA, including the ESTA statement. The airlines check each passenger's passport before boarding, to make sure that a digital link with an ESTA is in place. Travelers that try to enter the plane without an approved ESTA, US visa, or American passport are refused entry by the airline.
Second check: on arrival
Right after arrival by plane or by boat in the United States, travelers are checked by a clerk of the U.S. Customs and Border Protection agency. Despite the fact that all passengers at this point have already been checked for a valid travel permit (ESTA, US visa or US passport) it is possible that travelers are denied entry to US soil. This only happens if the customs clerk of the U.S. Customs and Border Protection agency suspects that a traveler poses a threat to the law enforcement and safety of the United States and its inhabitants. After running through the second check, travelers under the Visa Waiver Program are allowed to enter the USA.