Last time I filled in a visa waiver form it asked the following:
Visa Waiver Program
The first question on document I-94W for those visiting the U.S. on the
Visa Waiver Program asks:
Have you ever been arrested or convicted for an offense or crime involving moral turpitude or a violation related to a controled substance; or been arrested or convicted for two or more offenses for which the aggregate sentence to confinement was five years or more; or been controled substance trafficker; or are you seeking entry to engage in criminal or immoral activities?
Little guidance is provided to the traveler as to which offenses are included in the definition; however the Web site of the
U.S. embassy in London states that a
visa is required for anyone who has ever been arrested or convicted for
any offense.
[8] This appears to be at variance with the question on form I-94W and information supplied by the
U.S. Department of Homeland Security, as there are many offenses that are not considered to involve moral turpitude
http://en.wikipedia.org/wiki/Moral_turpitude
But now you have to fill in your personal details online 72 hours before departure at
https://esta.cbp.dhs.gov/esta/ so your application goes through prior extra scrutiny before departure.