Final answer:
If a law treats one person or class of people differently than others, it raises equal protection concerns, tied to the Equal Protection Clause of the Fourteenth Amendment intended to ensure legal equality.
Step-by-step explanation:
In general, if a law treats one person or class of people differently than others, it raises equal protection concerns. This concept is derived from the Equal Protection Clause, which is part of the Fourteenth Amendment of the United States Constitution. The clause requires that no state shall deny to any person within its jurisdiction "the equal protection of the laws". This is aimed to ensure that all people, particularly groups that have historically faced discrimination, are treated equally under the law.
Contrary to equal protection, procedural due process is concerned with the methods and procedures used by the government in enforcement and legislation, ensuring that these are fair and consistent. Meanwhile, substantive due process addresses the government's obligation to not enforce laws that interfere with constitutional liberties. The Privileges or Immunities Clause ensures certain rights are acknowledged and protected and does not normally pertain to the treatment difference amongst different classes of people.