A frail-looking Chief Justice William H. Rehnquist (search) made his first public appearance in months Thursday at President Bush's inauguration.

Rehnquist, a cane in his right hand, walked slowly without assistance down to the stage where he was swearing in the president.

He was diagnosed with thyroid cancer in October and has missed Supreme Court sessions for the past three months while receiving chemotherapy and radiation. He has mainly worked out of his town house in suburban Virginia.

Despite his illness, and a tracheotomy tube that helps him breathe, the 80-year-old chief justice decided to participate in the ceremony. It would be his fifth, and probably final, time swearing in the president.

The National Weather Service was predicting temperatures near 30 degrees in Washington on Thursday morning. It was unclear how the cold weather would affect Rehnquist's plans, although the Wisconsin native is known to require court staff to work in snowstorms.

A week ago, Rehnquist was at the Capitol to check out logistics for the event. He has occasionally worked out of his court office but has made no public appearances.

Rehnquist has been chief justice since 1986. Chief justices are traditionally asked to preside at swearing-in ceremonies. If Rehnquist had been unable to participate it would have been only the ninth time in history the chief justice did not administer the oath.