Magistrate judges aren't appointed by the President, because they're not Article III judges. They're selected by the circuit court - in this case, the Ninth.
Admin Moderator: please remove the reference to George H.W. Bush. It did seem out of character.
"Magistrate judges .. They're selected by the circuit court - in this case, the Ninth."
Not by the Circuit Court, by the District Court.
See:
"Magistrate judges are judicial officers of the district courts and are appointed by the judges of the district court for eight-year terms."
http://www.uscourts.gov/understand02/content_5_0.html