In 1986, the US Congress passed legislation creating the Visa Waiver Program to enable citizens from specific countries to be able to travel to the United States as a nonimmigrant to remain temporary in the US for tourist or business purposes. Basically, the law eliminated the necessity for citizens from to visa waiver countries from having to apply for a B1/B2 visa before leaving for the US. The limit on the waiver is 90 days total stay in the US.
There are now thirty six countries that are a part of the visa waiver program. The Department of State has an excellent website that explains what countries are involved in the program. One unique aspect of the program is the requirement that the country has to in turn permit US Citizens the same ability to visit that country for the same period for business and tourism purposes.
The current visa waiver program has specific requirements for those wishing to use it to travel to the United States. Each person who requests a waiver has to be able to provide their own passport showing he or she is a citizen of the qualifying country. The passport has to be valid for at least six months past the end of the visa waiver. The requirement now exists that the payment for the visa waiver has to be done online prior to travel.
It is important to note that the waiver program does not permit aliens who would have been denied obtaining a visa from also being denied the benefit of visa waiver. Those that are inadmissible at the port of entry will still be determined to be inadmissible upon inspection at the port of entry. This includes issues related to criminal history and prior overstays in previous visits to the US.
Aliens who are within the United States with a visa waiver cannot extend their stay beyond the 90 days as they could if they have a B1/B2 visa issued by a US Consulate. Also there is no right to appeal a denial at the port of entry if determined to be inadmissible by the agent.
It is advisable that an alien from a visa waiver country seek advice from an experienced immigration attorney prior to leaving their country to travel to the United States especially if there exists in the person's history any aspect that could make him/her inadmissible.