Answer:
Article 3, Section1 of the US Constitution states that "The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behavior, and shall, at stated Times, receive for their Services a Compensation which shall not be diminished during their Continuance in Office."
So, for President Bush to remove Justice Stevens, it would need to be shown that Justice Stevens was not acting with good behavior. This is a different threshold than Justice Stevens voting liberally and would likely involve a judge taking bribes, etc.
President Bush would not be able to remove Justice Stevens, instead Congress would have to have a trial and impeach the Justice after giving the Justice due process.
Step-by-step explanation: