WASHINGTON  — Conservative justices in the Supreme Court's majority are asking skeptical questions about President Joseph Biden’s plan to wipe away or reduce student loans held by millions of Americans.

The high court, with its 6-3 conservative majority, began hearing arguments on Tuesday in challenges to the plan. So far, Republican-appointed judges on lower courts have blocked the plan. The Biden administration says 26 million people have applied and 16 million have been approved to have up to $20,000 in federal student loans forgiven.

The program is estimated to cost $400 billion over 30 years.