Justice Ruth Bader Ginsburg missed oral arguments before the Supreme Court on Wednesday.

She is "indisposed due to illness," Chief Justice John Roberts said at the start of proceedings. She intended to participate in the consideration of the cases by reading briefs and transcripts, Roberts added.

Ginsburg, 86, is the oldest member of the court and the anchor of its liberal bloc. She has survived four bouts of cancer. If she were to die or retire, President Trump would have the opportunity to appoint a third justice to the high court, potentially cementing a 6-3 conservative majority for decades to come.

In August, Ginsburg completed radiation treatment for pancreatic cancer. Last year, she underwent surgery to remove two cancerous nodules found in her left lung. The justice was also treated for colon cancer in the late 1990s.

Story continues below

Ginsburg was on the bench for oral arguments Tuesday, when the justices considered legal challenges to Trump’s efforts to unwind the Deferred Action for Childhood Arrivals program. She was an active participant, posing the first question to Solicitor General Noel Francisco, who argued on behalf of the Trump administration.

President Bill Clinton named Ginsburg to the Supreme Court in 1993. She has vowed to remain on the high court until she is at least 90.

[Related: Ruth Bader Ginsburg, 86, says she’s ‘on my way to being very well’ after fourth bout of cancer]