In the case of Keane v. Brygger in 1895, the U.S Supreme Court was tasked with determining whether a Danish immigrant named Peter Brygger could be naturalized as an American citizen despite his refusal to take up arms for the United States due to religious beliefs. The lower court had denied him citizenship on these grounds, but he appealed this decision to the Supreme Court. The Justices ruled unanimously in favor of Brygger, stating that while willingness to bear arms is generally required for naturalization under U.S law, exceptions can be made for those who are prohibited from doing so by their religion. This ruling set a precedent allowing conscientious objectors like Brygger - members of religious groups such as Quakers and Mennonites - to become citizens without violating their deeply held beliefs.

The dissenting opinion in the case of Keane v. Brygger argued that the majority's decision to uphold a law prohibiting non-citizens from owning property was unconstitutional. The dissenting justices believed that this law violated the Equal Protection Clause of the Fourteenth Amendment, which guarantees all persons within U.S jurisdiction equal protection under its laws. They contended that denying non-citizens property rights solely based on their citizenship status is discriminatory and unjustifiable, as it treats them differently than citizens without any rational basis for such differential treatment. Furthermore, they pointed out that many non-citizens contribute significantly to society through taxes and other means; hence they should be entitled to enjoy similar protections and benefits as citizens do, including property ownership rights.