Which clause forbids retroactive criminal laws?

Which clause forbids retroactive criminal laws?

• A. Elastic Clause
• B. Due Process Clause
• C. Ex Post Facto Clause Article I, §9, clause 3
• D. Full Faith and Credit Clause

Answer: (C)

The Ex Post Facto Clause forbids retroactive criminal laws. It’s found in Article I, Section 9, Clause 3 of the U.S. Constitution and prevents Congress from making an act illegal after it was committed or from increasing punishment for past conduct. This protects people from being punished under laws that didn’t exist when they acted and keeps punishment associated with the law that was in place at the time of the offense. The clause applies to federal law, and through incorporation it influences state laws as well. The Elastic Clause grants Congress broader legislative power to enact laws necessary and proper to carry out its enumerated powers, not specifically about retroactivity. The Due Process Clause protects fair treatment and fundamental rights, but it doesn’t by itself ban retroactive criminalization; retroactive effects can raise due process concerns, yet the explicit prohibition is Ex Post Facto. The Full Faith and Credit Clause requires states to recognize laws and judgments of other states, not retroactivity of criminal laws.

The Ex Post Facto Clause forbids retroactive criminal laws. It’s found in Article I, Section 9, Clause 3 of the U.S. Constitution and prevents Congress from making an act illegal after it was committed or from increasing punishment for past conduct. This protects people from being punished under laws that didn’t exist when they acted and keeps punishment associated with the law that was in place at the time of the offense. The clause applies to federal law, and through incorporation it influences state laws as well.

The Elastic Clause grants Congress broader legislative power to enact laws necessary and proper to carry out its enumerated powers, not specifically about retroactivity. The Due Process Clause protects fair treatment and fundamental rights, but it doesn’t by itself ban retroactive criminalization; retroactive effects can raise due process concerns, yet the explicit prohibition is Ex Post Facto. The Full Faith and Credit Clause requires states to recognize laws and judgments of other states, not retroactivity of criminal laws.