[William Tell]

Congressman Billybob said: Now, it isn’t proper to ask a prospective new Justice a bald-faced question, “Do you think the Kelo decision was bad, and should be reversed?” Any nominee who answered that question would have to disqualify himself/herself when a new case on that issue found its way into the Court."

I don't understand this.

Every member of the Court which decided Kelo is in the same position. They reviewed the facts, heard the arguments, and came to a decision. How is the fact that a nominee does the same thing when questioned by the Senate act as a disqualifier when having actually ruled in the original case, whether concurring or dissenting, does not?

[MortMan]

It's called (hyphen inserted for emphasis) pre-judice (prejudging the outcome of a specific case). When a decision has been made during the course of a previous case ("in the line of duty", as it were), the principle doesn't apply.