The analysis used to apply an individual right was a legal distinction between the Prefatory Clause and the Operative Clause.
Syllabus from Heller:
(a) The Amendment’s prefatory clause announces a purpose, but does not limit or expand the scope of the second part, the operative clause. The operative clause’s text and history demonstrate that it connotes an individual right to keep and bear arms. Pp. 2–22.
(b) The prefatory clause comports with the Court’s interpretation of the operative clause. The “militia” comprised all males physically capable of acting in concert for the common defense. The Antifederalists feared that the Federal Government would disarm the people in order to disable this citizens’ militia, enabling a politicized standing army or a select militia to rule. The response was to deny Congress power to abridge the ancient right of individuals to keep and bear arms, so that the ideal of a citizens’ militia would be preserved. Pp. 22–28.
(c) The Court’s interpretation is confirmed by analogous arms-bearing rights in state constitutions that preceded and immediately followed the Second Amendment . Pp. 28–30.
Syllabus from Heller:
(a) The Amendment’s prefatory clause announces a purpose, but does not limit or expand the scope of the second part, the operative clause. The operative clause’s text and history demonstrate that it connotes an individual right to keep and bear arms. Pp. 2–22.
(b) The prefatory clause comports with the Court’s interpretation of the operative clause. The “militia” comprised all males physically capable of acting in concert for the common defense. The Antifederalists feared that the Federal Government would disarm the people in order to disable this citizens’ militia, enabling a politicized standing army or a select militia to rule. The response was to deny Congress power to abridge the ancient right of individuals to keep and bear arms, so that the ideal of a citizens’ militia would be preserved. Pp. 22–28.
(c) The Court’s interpretation is confirmed by analogous arms-bearing rights in state constitutions that preceded and immediately followed the Second Amendment . Pp. 28–30.