Which Amendment requires states to provide due process and equal treatment for all individuals?

The 14th Amendment is the key provision in the U.S. Constitution that mandates states to provide due process and equal protection under the law for all individuals. Ratified in 1868, the 14th Amendment was largely a response to the injustices faced by newly freed slaves in the post-Civil War era. Its Due Process Clause prohibits states from depriving any person of life, liberty, or property without due process of law, ensuring fair treatment through the judicial system.

Furthermore, the Equal Protection Clause, also part of the 14th Amendment, requires states to provide equal protection of the laws to all individuals within their jurisdiction. This has been pivotal in various landmark Supreme Court cases that addressed civil rights and discrimination.

The other amendments listed do not address due process or equality in the same comprehensive manner as the 14th Amendment. The First Amendment focuses on freedoms such as religion and speech, the Fifteenth Amendment pertains to voting rights and prohibits denying the right to vote based on race, while the Nineteenth Amendment grants women the right to vote but does not directly address due process or broader equality principles. Therefore, the 14th Amendment stands out as the primary source for these constitutional protections.