Which amendment prohibits states from denying equal protection?

The 14th Amendment is pivotal in American constitutional law as it explicitly prohibits states from denying any person within their jurisdiction equal protection of the laws. Ratified in 1868, this amendment was a significant step towards civil rights, particularly addressing issues of racial discrimination and ensuring that all individuals receive the same legal protections, regardless of race, color, or previous condition of servitude.

In the context of U.S. law, the equal protection clause has served as the foundation for landmark Supreme Court cases that have sought to address and rectify inequalities. It mandates that individuals in similar situations be treated equally by the law, thereby promoting fairness and justice across different states.

The other choices do not pertain to equal protection. The 10th Amendment deals with the powers reserved to the states, the 15th Amendment addresses voting rights regardless of race, and the 18th Amendment established Prohibition. These amendments serve different purposes within the scope of civil rights and governance but do not directly relate to the principle of equal protection under the law.