Politics Obama announces key adviser Denis McDonough as his fifth chief of staff January 25, 2013 | Modified: January 25, 2013 at 1:16 pm Leave a comment WASHINGTON (AP) — Obama announces key adviser Denis McDonough as his fifth chief of staff. Sign Up for the Politics Digest newsletter! Please enter your email address below to begin receiving the Politics Digest newsletter. You must enter a valid email address in the field above! Thank you for signing up for the Politics Digest newsletter! You should receive your first newsletter very soon. We're sorry, there was an error processing your newsletter signup. Please click here to visit our Newsletter Signup Center to register for this newsletter.