Final answer:
The Constitution forbids states from passing laws that unfairly favor their own citizens, requires them to honor acts and proceedings of other states, and mandates congressional approval for interstate agreements. However, it doesn't prohibit states from regulating licensing and private property.
Step-by-step explanation:
The Constitution places certain constraints on the powers of both the federal government and the state governments. For instance, states are prohibited from passing laws that favor their own citizens over those from other states, as per Article IV, Section 2, also known as the Privileges and Immunities Clause. Additionally, states must honor the public acts and judicial decisions of other states, a mandate that facilitates the national cohesion and prevents legal discrepancies across state lines.
While states have a measure of sovereignty, they require congressional approval to enter into agreements with one another, reflecting the overarching authority of the federal government as established in Article I, Section 10 of the Constitution. However, the notion that the Constitution prohibits states from regulating licensing and private property is incorrect. States retain the power to regulate these areas, provided they do not conflict with federal laws or constitutional rights.