No, an N-600 may NOT be filed FROM abroad for the VAST Majority of applicants.
Making a foreign trip while it is pending is quite a different matter than sending the form from abroad. ONLY a few folks are allowed to do so. That narrow class is comprised of military members and their families as only recently enacted for all application pertaining to naturalization and citizenship. (Even more recently a special tolling provision has been passed into law in regard to filing I-751's by military members and spouses--it was totally unnecessary but politicians do like to pander for votes, so it passed.)
Section 674(a) of Public Law 110-181 , dated January 28, 2008, amended section INA 319 by adding a new subsection (e), and amended section 322 by adding a new subsection (d).
Section 673 of Public Law 110-181 , dated January 28, 2008, amended section INA 284 by striking `Nothing' and inserting `(a) Nothing' and by adding subsection (b).
EFFECTIVE DATE: The amendments made by this section shall take effect on the date of enactment of this Act (January 28, 2008) and apply to any application for naturalization or issuance of a certificate of citizenship pending on or after such date.
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USCIS regulations have just been amended in an Aug. 29, 2011, rule published in the Federal Register. It is effective as of Nov. 28, 2011.
This rule adds 8 CFR 316.6 and revises 8 CFR 316.5, 8 CFR 322.2, and 8 CFR 341.5 to conform to the amendments to the Act by the National Defense Authorization Act (NDAA 2008), Public Law 110–181, 122 Stat. 3 (Jan. 28, 2008). The NDAA 2008 provides certain immigration benefits for any qualifying spouse or child of a member of the Armed Forces.
In addition, numerous regulations have been changed in order to drop much procedural language and instead invoke the form instructions and the form instructions say that a person residing outside the United States may not file. The narrow exception for military members and dependents is based on a different INA sections pertaining to constructive physical presence and residence as well as an associated exception for children adopted abroad by USCs residing abroad. Lastly, a special provision calling for special treatment of military members
See also newly revised 8 CFR PART 341--CERTIFICATES OF CITIZENSHIP
§ 341.1
An application for a certificate of citizenship by or in behalf of a person who claims to have acquired United States citizenship under section 309(c) of the Act or to have acquired or derived United States citizenship as specified in section 341 of the Act must be submitted on the form designated by USCIS with the fee specified in 8 CFR 103.7(b)(1) and in accordance with the instructions on the form.
§ 341.5
(c) Approval pursuant to section 322(d) of the Act. Persons eligible for naturalization pursuant to section 322(d) of the Act may subscribe to the oath of renunciation and allegiance and may be issued a certificate of citizenship outside of the United States, in accordance with 8 U.S.C. 1443a.
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8 USC § 1443a. Naturalization proceedings overseas for members of the Armed Forces
Notwithstanding any other provision of law, the Secretary of Homeland Security, the Secretary of State, and the Secretary of Defense shall ensure that any applications, interviews, filings, oaths, ceremonies, or other proceedings under title III of the Immigration and Nationality Act (8 U.S.C. 1401 et seq.) relating to naturalization of members of the Armed Forces are available through United States embassies, consulates, and as practicable, United States military installations overseas.
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INA Title III NATIONALITY AND NATURALIZATION
CHAPTER 2 -- NATIONALITY THROUGH NATURALIZATION
INA 332 [8 U.S.C. 1443] PROCEDURAL AND ADMINISTRATIVE PROVISIONS; EXECUTIVE FUNCTIONS
(a) The [Secretary of Homeland Security] shall make such rules and regulations as may be necessary to carry into effect the provisions of this chapter and is authorized to prescribe the scope and nature of the examination of applicants for naturalization as to their admissibility to citizenship. Such examination shall be limited to inquiry concerning the applicant's residence, physical presence in the United States, good moral character, understanding of and attachment to the fundamental principles of the Constitution of t he United States, ability to read, write, and speak English, and other qualifications to become a naturalized citizen as required by law, and shall be uniform throughout the United States.
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INA 284. [8 U.S.C. 1354] MEMBERS OF THE ARMED FORCES
(a) Nothing contained in this title shall be construed so as to limit, restrict, deny, or affect the coming into or departure from the United States of an alien member of the Armed Forces of the United States who is in the uniform of, or who bears documents identifying him as a member of, such Armed Forces, and who is coming to or departing from the United States under official orders or permit of such Armed Forces: Provided, That nothing contained in this section shall be construed to give to or confer upon any such alien any other privileges, rights, benefits, exemptions, or immunities under this Act, which are not otherwise specifically granted by this Act.
(b) If a person lawfully admitted for permanent residence is the spouse or child of a member of the Armed Forces of the United States, is authorized to accompany the member and reside abroad with the member pursuant to the member's official orders, and is so accompanying and residing with the member (in marital union if a spouse), then the residence and physical presence of the person abroad shall not be treated as-
(1) an abandonment or relinquishment of lawful permanent resident status for purposes of clause (i) of section 101(a)(13)(C) ; or
(2) an absence from the United States for purposes of clause (ii) of such section.
.....and there is more than just that.