Immigration law delegates the responsibility for issuance or refusal of visas to consular officers overseas. They have the final say on all visa cases. By regulation, the U.S. Department of State has authority to review consular decisions, but this authority is limited to the interpretation of law, as contrasted to determinations of facts. The question at issue in such denials, whether an applicant possesses the required residence abroad, is a factual one. Therefore, it falls exclusively within the authority of consular officers at our Foreign Service posts to resolve. An applicant can influence the post to change a prior visa denial only through the presentation of new convincing evidence of strong ties.
Entering a country without a valid visa or visa exemption may result in detention and removal (deportation or exclusion) from the country. Undertaking activities that are not authorised by the status of entry (for example, working while possessing a non-worker tourist status) can result in the individual being deemed liable for deportation—commonly referred to as an illegal alien. Such violation is not a violation of a visa, despite the common misuse of the phrase, but a violation of status; hence the term "out of status".
Nepal and India allow their citizens to enter, live and work in each other's countries due to the Indo-Nepal friendship treaty of 1951. Indians do not require a visa or passport to travel to Bhutan and are only required to obtain passes at the border checkpoints, whilst Bhutan nationals holding a valid Bhutanese passport are authorised to enter India without a visa.
Countries have visa restrictions in order to check and control the flow of visitors in and out of the country and to prevent illegal immigration and other criminal activities. Forcing travellers to apply for a visa allows the authorities to vet potential visitors. For example, individuals may attempt to travel to a country with better economic opportunities in order to work illegally there.
Kuwait, Lebanon, Libya, Saudi Arabia, Sudan, Syria, and Yemen do not allow entry to people with passport stamps from Israel or whose passports have either a used or an unused Israeli visa, or where there is evidence of previous travel to Israel such as entry or exit stamps from neighbouring border posts in transit countries such as Jordan and Egypt.