Final answer:
The presumption of constitutionality stands unless there is clear evidence or intent proving that a law is unconstitutional. This principle is rooted in the idea that the Constitution is the highest law of the nation, and it safeguards individual rights and maintains checks and balances. Key examples include prohibitions on bills of attainder, ex post facto laws, and the protection of free speech and due process.
Step-by-step explanation:
The presumption of constitutionality must prevail in the absence of substantial evidence or clear legislative intent indicating that a law is unconstitutional. This legal principle recognizes that legislative acts come with a heavy presumption in favor of their validity. It is only when a law is clearly in conflict with the Constitution, which is regarded as the supreme law of the land, that the law can be considered invalid. This concept was underscored in decisions such as the one involving Section 13 of the Judiciary Act of 1789, where the Supreme Court, through the leadership of Chief Justice John Marshall, declared an act of Congress void if it is repugnant to the Constitution. The Constitution contains several explicit prohibitions to protect individual rights and maintain a system of checks and balances. For instance, it specifically outlaws bills of attainder and ex post facto laws, ensuring that individuals cannot be penalized without a fair trial, and actions cannot be made illegally retroactive. Additionally, laws must not abridge the privileges or immunities of citizens, deny due process, or infringe upon the equal protection of the laws.
Furthermore, the First Amendment imposes a high burden on any government action that would exert prior restraint on speech, holding that only in extreme circumstances can the government prevent expression before it happens. The Constitution also affirms rights such as the writ of habeas corpus, which protects individuals from unlawful detention.