The Constitution provides that Congress may provide protections involving copyrights and trademarks for limited times.
For many decades, copyright lasted 17 or 34 years or other similar times. Suddenly, Copyright is out to infinity, almost. Cynics proposed that ABC/Disney had lobbied vigorously, in essence to give themselves ownership of the rodent in perpetuity.
Some member of Congress would need to submit a bill, restoring the Constitution's intent of protection for limited times.
The rest is left up to the reader.