No previous job prepares a person to be president.
I believe that all would be good choices for vice president and good presidents.
Senator Obama choose one of these people:
Governor Bill Richardson of New Mexico
Governor Chris Gregoire of Washington
Governor Joe Manchin of West Virginia
Governor Janet Napolitano of Arizona
Representative Ron Paul of Texas
Senator Claire McCaskill of Missouri
Representative Artur Davis of Alabama
Susan Eisenhower, president of the Eisenhower Group, Inc.
Senator Ron Wyden of Oregon
Representative Tammy Suzanne Green Baldwin of Wisconsin
Senator Bernie Sanders of Vermont