Which clause prevents discrimination among citizens of different states?

The Equal Protection Clause is crucial in preventing discrimination among citizens of different states. It is part of the Fourteenth Amendment and mandates that no state shall deny to any person within its jurisdiction the equal protection of the laws. This clause is foundational in promoting fairness and equality, ensuring that individuals in similar situations are treated alike, regardless of state lines.

This mechanism is especially important when considering how states interact with one another and their citizens. Discrimination based on residency or state citizenship would violate the principles of equality that the clause upholds, allowing individuals from one state to challenge discriminatory practices that could disadvantage them in another state, thus fostering a sense of national uniformity in terms of legal protections.

Other options refer to different aspects of legal protections: the Due Process Clause primarily deals with the legal rights of individuals to fair treatment under the law, the Full Faith and Credit Clause mandates that states honor each other's laws and judicial decisions, and the Necessary and Proper Clause grants Congress the power to pass laws necessary to carry out its constitutional duties. While these clauses are significant in their respective contexts, they do not specifically address the issue of discrimination among citizens from different states the way the Equal Protection Clause does.