Presser v. Illinois was a United States Supreme Court case that addressed the right to bear arms. The case was brought by Herman Presser, a member of the Lehr und Wehr Verein, a German-American militia organization. Presser was charged with violating an Illinois law that prohibited private military organizations from marching or parading with firearms in public. Presser argued that the law violated the Second Amendment of the United States Constitution, which states that "the right of the people to keep and bear arms shall not be infringed." The Supreme Court ruled in favor of the state of Illinois, finding that the Second Amendment only applies to the federal government and does not limit the power of the states to regulate the right to bear arms. The Court reasoned that the Second Amendment was intended to protect the right of the people to form a militia, and that the state of Illinois had the right to regulate the formation and activities of private militias. The Court also noted that the Second Amendment does not guarantee the right to bear arms in public, and that the state of Illinois had the right to regulate the bearing of arms in public. In conclusion, the Supreme Court held that the Second Amendment does not limit the power of the states to regulate the right to bear arms, and that the state of Illinois had the right to regulate the formation and activities of private militias, as well as the bearing of arms in public.

In Presser v. Illinois, the Supreme Court was asked to decide whether a state law that prohibited private citizens from forming or joining military organizations without permission violated the Second Amendment of the United States Constitution. The majority opinion held that it did not violate the Second Amendment because it only regulated private militia groups and did not prevent individuals from keeping and bearing arms for their own protection. However, in his dissent, Justice Field argued that this law infringed upon an individual's right to keep and bear arms as protected by both the Second Amendment and Article I Section 8 of the U.S Constitution which gives Congress power "to provide for organizing, arming, and disciplining" militias composed of civilians who are members of a well-regulated militia necessary to protect states against invasion or insurrection. He further argued that since these rights were granted by federal laws they could not be taken away by any state government through legislation such as this one which attempted to do so under its police powers authority over public safety matters within its borders.