How come a mere small shoplifting becomes a deportable offense while applying for Citizenship? Please let me know if such incidents occured in past.
Can you or anyone send any such rules/law which I can read?
In principle, even a shoplifting conviction could make one deportable under some circumstances.
See:
http://www.law.cornell.edu/uscode/8/usc_sec_08_00001227----000-.html
"(A) General crimes
(i) Crimes of moral turpitude Any alien who—
(I) is convicted of a crime involving moral turpitude committed within five years (or 10 years in the case of an alien provided lawful permanent resident status under section 1255 (j) of this title) after the date of admission, and
(II) is convicted of a crime for which a sentence of one year or longer may be imposed,
is deportable.
(ii) Multiple criminal convictions. Any alien who at any time after admission is convicted of two or more crimes involving moral turpitude, not arising out of a single scheme of criminal misconduct, regardless of whether confined therefor and regardless of whether the convictions were in a single trial, is deportable."
Any kind of theft is a crime involving moral turpitude, so if the specific state statute under which you were convicted allows for a sentence of one year or more (even if you received no jail sentence), and if the conviction occurred with 5 years of your initial admission to the U.S. [which is probably not the case for you], then (A)(i) above would apply.
Also, if one has more than one criminal conviction for crimes involving moral turpitude (even if they are for minor theft offenses), then (A)(ii) above applies.
IMO, it is fairly unlikely that you are deportable, although it is a good idea to check with an immigration lawyer on this point before submitting an N-400.
However, regardless of the deportability question, you are, for the moment, not eligible for naturalization because of your 2008 shoplifting conviction. Any theft is a CIMT (crime involving moral turpitude); by law, you cannot be found to have good moral character if at the time of filing N-400 you have a CIMT conviction that is less that 5 years old (3 years for marriage-based naturalization cases):
See 8 C.F.R. § 316.10:
http://law.justia.com/cfr/title08/8-1.0.1.3.68.0.1.7.html
"(2) An applicant shall be found to lack good moral character if during the statutory period the applicant:
(i) Committed one or more crimes involving moral turpitude, other than a purely political offense, for which the applicant was convicted, except as specified in section 212(a)(2)(ii)(II) of the Act;"
So you need to wait at least 5 years from the date of your 2008 shoplifting conviction (3 years, if N-400 is based on marriage to a U.S. citizen) before you can file N-400.