President Joe Biden’s plan to forgive student loan debt for tens of millions of Americans seems to be in danger based on oral arguments at the Supreme Court on Tuesday.

A majority of justices appeared dubious about the Biden administration’s pandemic-related legal justification for the sweeping debt relief program, which offered up to $20,000 of loan forgiveness per borrower. The initiative has been put on hold while the high court debates the case.

During more than three hours of oral argument, conservative justices on the court repeatedly questioned whether the Education Department had the legal authority it claimed to discharge federal student loan debt to help borrowers recover economically from the national emergency spurred by Covid-19.