An applicant for naturalization must be willing to take up arms in defense of the United States when required by law; an unwillingness to do so, even if based on pacifist beliefs, demonstrates a lack of attachment to the principles of the Constitution and an inability to take the oath of allegiance without mental reservation, thereby disqualifying the applicant for citizenship.

The case arose from Rosika Schwimmer's application for naturalization under the Naturalization Act of 1906. At the time, international tensions and the experience of World War I had heightened concerns about national loyalty and the obligations of citizenship, including the duty to defend the country. Schwimmer, a well-known lecturer and writer with strong pacifist convictions, sought U.S. citizenship, leading to a legal challenge regarding whether her refusal to bear arms was compatible with the requirements for naturalization.

• Rosika Schwimmer, born in Hungary in 1877, came to the United States in August 1921, and filed a petition for naturalization in September 1926.
• On a preliminary naturalization form, in response to the question "If necessary, are you willing to take up arms in defense of this country?", she answered: "I would not take up arms personally."
• Schwimmer was a 49-year-old woman (at the time of initial proceedings), a linguist, lecturer, and writer, well-educated and accustomed to discussing government and civic affairs.
• She testified she was an "uncompromising pacifist" with "no sense of nationalism, only a cosmic consciousness of belonging to the human family."
• She stated she could wholeheartedly take the oath of allegiance and did not see a woman's refusal to take up arms as a contradiction to the oath.
• She expressed willingness to support and defend the Constitution and laws in other ways, such as through civic engagement and opposing undemocratic forms of government.
• Schwimmer reiterated at the hearing her unwillingness to bear arms, stating: "If American women would be compelled to do that, I would not do that. I am an uncompromising pacifist."
• She indicated she was willing to be treated as the government dealt with male conscientious objectors who refuse to take up arms.
• The District Court found her unable, without mental reservation, to take the prescribed oath of allegiance, not attached to the principles of the Constitution, and not well disposed to the good order and happiness of the same.

• The United States argued that naturalization statutes must be construed to favor and support the Government.
• The burden is on the applicant to show by satisfactory evidence that they possess the specified qualifications for citizenship.
• The duty of citizens to defend the Government by force of arms whenever necessity arises is a fundamental principle of the Constitution.
• An unwillingness to bear arms, even for a woman potentially exempt from service, indicates a lack of attachment to Constitutional principles and an inability to take the oath of allegiance without reservation.
• Schwimmer's pacifism and lack of nationalistic sense, coupled with her refusal to bear arms, showed she was not attached to the principles of the Constitution as required by the Naturalization Act.
• Her views could influence others to oppose military defense, thereby detracting from the strength and safety of the Government.

• Rosika Schwimmer argued that she was qualified for citizenship and could take the oath of allegiance without mental reservation.
• She contended that a woman's refusal to personally bear arms, especially given her age and sex, was not inconsistent with the oath of allegiance or attachment to Constitutional principles.
• She asserted her commitment to democratic ideals and her willingness to defend the Constitution through non-violent means.
• She believed her pacifism and "cosmic consciousness" were compatible with American citizenship and that she was willing to do everything an American citizen has to do except fighting.

• Whether an applicant for naturalization who is unwilling to take up arms in defense of the United States is "attached to the principles of the Constitution of the United States, and well disposed to the good order and happiness of the same" as required by the Naturalization Act.
• Whether such an applicant can take the oath of allegiance, which requires supporting and defending the Constitution and laws of the United States against all enemies, without mental reservation.

• The Supreme Court reversed the decree of the Circuit Court of Appeals and affirmed the decree of the District Court, denying Schwimmer's application for naturalization.
• The Court reasoned that the duty of citizens to defend the government by force of arms is a fundamental principle of the Constitution.
• An applicant for citizenship must be willing to take up arms when necessary, and an unwillingness to do so, regardless of the applicant's sex or age, demonstrates a lack of the required attachment to Constitutional principles.
• Schwimmer's statements, taken as a whole, showed her objection to military service was based on reasons other than mere inability due to age or sex, and her pacifism and lack of nationalistic sense were inconsistent with the true faith and allegiance required by the Naturalization Act.
• The Court held that when doubt remains as to an essential matter of fact in a naturalization application, the United States is entitled to the benefit of that doubt, and the application should be denied.
• Schwimmer failed to meet the burden of showing that her pacifism did not oppose the principle of defending the country by arms and that her beliefs would not impair the true faith and allegiance required.

• Statutory Construction of Naturalization Laws — This principle dictates that statutes prescribing qualifications for naturalization are to be construed with a definite purpose to favor and support the Government due to the great value of the privileges conferred. The Court applied this by interpreting the requirements for allegiance and attachment to the Constitution strictly, in a way that supports the government's interest in national defense.
• Burden of Proof in Naturalization Proceedings — The law places the burden upon every applicant to show by satisfactory evidence that they possess the specified qualifications for citizenship. The Court found Schwimmer failed to sustain this burden regarding her attachment to the principles of the Constitution and her ability to take the oath without reservation, particularly concerning the duty to defend the nation by arms.
• Duty of Citizens to Defend the Government — This is a fundamental principle of the Constitution, implying that citizens have a reciprocal obligation to render military service in case of need. The Court held that Schwimmer's unwillingness to bear arms was contrary to this fundamental duty and thus showed a lack of attachment to constitutional principles.
• Attachment to the Principles of the Constitution — This requirement for naturalization means more than abstract approval; it includes a willingness to support and defend the Constitution and the government established thereunder, including by bearing arms if necessary. Schwimmer's pacifist stance was deemed inconsistent with this requirement.
• Resolution of Doubt in Favor of the Government in Naturalization Cases — When, upon fair consideration of the evidence, doubt remains in the mind of the court as to any essential matter of fact, the United States is entitled to the benefit of such doubt, and the application should be denied. The Court applied this by stating that Schwimmer's vague and ambiguous language regarding her attitude towards constitutional principles, and her failure to clarify that her pacifism did not oppose the duty to defend by arms, created such a doubt.

• "That it is the duty of citizens by force of arms to defend our Government against all enemies whenever necessity arises, is a fundamental principle of the Constitution."
• "Citizenship is a high privilege and when doubts exist concerning a grant of it, generally at least, they should be resolved in favor of the United States and against the claimant."
• "Whatever tends to lessen the willingness of citizens to discharge their duty to bear arms in the country's defense detracts from the strength and safety of the Government."
• "The influence of conscientious objectors against the use of military force in defense of the principles of our Government is apt to be more detrimental than their mere refusal to bear arms."
• (From Holmes, J., dissenting) "...if there is any principle of the Constitution that more imperatively calls for attachment than any other it is the principle of free thought—not free thought for those who agree with us but freedom for the thought that we hate."

• Luria v. United States, 231 U. S. 9, 22 — Cited to establish that naturalized citizens stand on the same footing as native-born citizens, owing allegiance to the Government, which in turn owes them protection, these being reciprocal obligations.
• Tutun v. United States, 270 U. S. 568, 578 — Referenced for the principle that the law puts the burden upon every applicant for naturalization to show by satisfactory evidence that they have the specified qualifications.
• United States v. Ginsberg, 243 U. S. 472, 475 — Cited alongside Tutun to support the principle of the applicant's burden of proof and that naturalization statutes are to be construed to favor the government.
• Spratt v. Spratt, 4 Pet. 393, 408 — Quoted for the court's function in naturalization applications: "to receive the testimony, to compare it with the law, and to judge on both law and fact."
• United States v. Manzi, 276 U. S. 463, 467 — Cited for the rule that doubts concerning a grant of citizenship should be resolved in favor of the United States and against the claimant.
• Selective Draft Law Cases, 245 U. S. 366, 378 — Referenced for the statement that "the very conception of a just government and its duty to the citizen includes the reciprocal obligation of the citizen to render military service in case of need."

• Naturalization Act of June 29, 1906 (U.S.C., Tit. 8, § 381) — This section requires an applicant for naturalization to declare on oath that they will support and defend the Constitution and laws of the United States against all enemies and bear true faith and allegiance to the same. The Court found Schwimmer's unwillingness to bear arms incompatible with this oath.
• Naturalization Act of June 29, 1906 (U.S.C., Tit. 8, § 382) — This section requires it to be made to appear to the satisfaction of the court that the applicant has behaved as a person of good moral character, attached to the principles of the Constitution, and well disposed to the good order and happiness of the United States. The Court held Schwimmer failed to demonstrate the required attachment due to her pacifist stance against bearing arms.
• The Constitution of the United States (general principles) — The Court referred to the Constitution's provisions for common defense (e.g., empowering Congress to declare war, raise armies, etc.) as establishing the fundamental duty of citizens to defend the government by arms.

• Mr. Justice Holmes — Justice Holmes, with Justice Brandeis concurring, dissented, arguing that Schwimmer was a woman of superior character and intelligence, desirable as a citizen. He contended that her pacifism and unwillingness to bear arms (especially given her age and sex, making her unlikely to be called to service) did not demonstrate a lack of attachment to the Constitution. He emphasized the principle of free thought, "not free thought for those who agree with us but freedom for the thought that we hate," suggesting that her optimistic belief in the eventual abolition of war should not disqualify her. He found her examination a better argument for her admission than any against it.
• Mr. Justice Sanford — Justice Sanford dissented separately, stating that he agreed in substance with the views expressed by the Circuit Court of Appeals and believed its decree (which would have granted citizenship) should be affirmed.