Final answer:
According to Martin Luther King Jr., just laws align with universal fairness, as supported by natural law theory, while unjust laws do not. This distinction emphasizes that the enforcement of laws should consider circumstances to ensure equity. The aim of a government should be to create laws that serve society's welfare.
Step-by-step explanation:
The distinction that King draws between two types of laws in his letter is that just laws are rooted in universal principles of fairness, while unjust laws are not. Evoking Aquinas, King professes that human laws must be modeled on natural law to be just. This is underscored by his argument that any law that uplifts human personality is just and any law that degrades human personality is unjust.
In terms of how we evaluate just laws today, they often vary in harshness according to circumstances to ensure fairness. Unjust laws tend to neglect these circumstances, applying the same rules and punishments indiscriminately, which may be contrary to societal values and context-specific realities. Subsequently, the enforcement of laws in a just society requires a consideration of the equitable treatment of individuals, which is supported by ideas from ethical naturalism, social justice theories, and classical natural law theory.
Keeping in mind societal welfare and logic, the function of government is to enact laws that protect and improve lives, echoing the ideals of philosophers like John Locke, reflecting modern standards of legislation aimed at the common good.