Final answer:
The Tenth Amendment of the Constitution is frequently invoked to support arguments for increased states' rights, as it reserves all non-delegated powers to the states or the people.
Step-by-step explanation:
The part of the Constitution that is often used to justify arguments supporting increased states' rights is the Tenth Amendment. This amendment is sometimes referred to as the reserved powers clause because it reserves to the states all powers not delegated to the United States by the Constitution or prohibited by it.
The text of the Tenth Amendment establishes that "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." Therefore, this provision serves as a foundation for federalism, reinforcing the idea that the federal government is one of enumerated powers and the states have broad powers to regulate matters not expressly controlled by the federal government.