The federal law concerning inadmissibility of aliens into the U.S. is codified at:
8 United States Code § 1182- Inadmissible aliens
http://www4.law.cornell.edu/uscode/8/1182.html
Here is the pertinent part of the code:
Sec. 1182. - Inadmissible aliens
(a) Classes of aliens ineligible for visas or admission
Except as otherwise provided in this chapter, aliens who are
inadmissible under the following paragraphs are ineligible to receive
visas and ineligible to be admitted to the United States:
....
2) Criminal and related grounds
(A) Conviction of certain crimes
(i) In general
Except as provided in clause (ii), any alien convicted of, or who
admits having committed, or who admits committing acts which
constitute the essential elements of -
(I)
a crime involving moral turpitude (other than a purely political
offense) or an attempt or conspiracy to commit such a crime, or
(II)
a violation of (or a conspiracy or attempt to violate) any law or
regulation of a State, the United States, or a foreign country
relating to a controlled substance (as defined in section 802 of title
21), is inadmissible."
source:
8 United States Code § 1182- Inadmissible aliens
http://www4.law.cornell.edu/uscode/8/1182.html
DRUNK DRIVING IS CONSIDERED a crime involving moral turpitude in many cases
Thus a US immigration officer has the LEGAL GROUND TO DENY YOU ENTRY TO THE USA. I HAVE SEEN IT HAPPEN DAILY.