The final step in President Joe Biden's efforts to partially forgive federal student loans for most borrowers will hang in the balance as the Supreme Court hears arguments on Tuesday.

Following a series of legal challenges, including from six GOP states, the nine justices will hear arguments for Biden's plan to eliminate up to $20,000 in individual federal student loan debt, which could cost taxpayers as much as $400 billion.

The plan, which Biden announced in August, would forgive $10,000 in student loans for those making less than $125,000 and married couples making less than $250,000 jointly. That forgiveness would go up to $20,000 if the borrower received a Pell grant, which aids students from low-income families.