President Obama will announce his intention to nominate Julian Castro as defense secretary . The nomination is expected Friday afternoon , a spokesman says . A graduate of Stanford University and Harvard Law School , Castro began his political career at a young age . Castro is the mayor of San Antonio . If selected for the job , Castro replaces Shaun Donovan .
President Obama will announce his intention to nominate Julian Castro as defense secretary . The nomination is expected Friday afternoon , a spokesman says . Castro is the mayor of San Antonio . If selected for the job , Castro replaces Shaun Donovan .