[af_vet_1981]

It would take a Constitutional amendment. Indian sovereignty is recognized in the Constitution. Yes it’s outdated but it’s clearly there.

Sure, just like the "right to privacy."

"The US Constitution does not specifically mention Native American sovereignty"

The United States can nullify a treaty through a combination of legislative and executive actions, though there is ongoing debate over the exact division of power. Congress can abrogate a treaty with a subsequent law, and the President can terminate a treaty through executive action, sometimes following terms in the treaty itself or international law. The Supreme Court has established that Congress has the power to pass a law that contradicts a treaty, making the treaty ineffective within the U.S. legal system

[Reily]

Indian Tribes are specifically mentioned in two clauses in the main body and in the 14th Amendment.

Article I, Section 2: This section states that “Representatives and direct Taxes shall be apportioned among the several States ... excluding Indians not taxed.”

This clause reflects the status of Native Americans at the time the Constitution was written, indicating that they were not considered part of the American body politic and were not subject to taxation or representation

Article I, Section 8, Clause 3 (Indian Commerce Clause): This clause grants Congress the power “to regulate Commerce with the Indian Tribes.”

This establishes a significant federal authority over tribal affairs, allowing Congress to enact laws that affect tribal governance and commerce.

Fourteenth Amendment, Section 2: This amendment modifies the earlier clause regarding representation, further clarifying the status of “Indians not taxed” in the apportionment of representatives

Also they are recognized to have “inherent sovereignty”.
Inherent Sovereignty: Native American tribes possess inherent sovereignty, meaning their authority to govern themselves predates the U.S. Constitution. This sovereignty is recognized and affirmed by the Constitution, allowing tribes to maintain their internal governance and legal systems.