Neither justice is budging.
Many ethicists and legal experts say that's the right decision.
None of the parties in the case has asked the justices to withdraw.
But behind the calls from both sides is the belief that the conservative Thomas is a sure vote to strike down President Barack Obama's health care law and that the liberal Kagan is certain to uphold the main domestic achievement of the man who appointed her.
The stakes are high in the court's election-year review of the law, which is intended to extend coverage to more than 30 million people.