Roberts nominated as Chief Justice

It will be Thursday at the earliest before the Senate starts confirmation hearings on the nomination of John

to be chief justice.

Originally, the Senate Judiciary Committee was going to begin hearings tomorrow on Roberts' nomination to succeed Sandra Day O'Connor on the high court. But that plan has been scrapped, now that Roberts has been nominated instead to succeed the late William Rehnquist as chief justice.

It's a nomination that could shape the court for decades to come. Roberts is just 50 years old.

If he's confirmed as chief justice, the court would apparently remain at full strength. O'Connor has said she'll remain on the job until her replacement is confirmed.

As he made the announcement this morning, Bush called Roberts "a man of integrity and fairness." Roberts said he's "honored and humbled" to be chosen to succed a man he deeply respects and admires.

Senate Majority Leader Bill Frist says he still expects Roberts to be confirmed before the new court session begins, four weeks from today. He calls Roberts an "excellent choice."

But Democratic leader Harry Reid says the stakes are now higher -- and that "the Senate must be vigilant."