Protest about the president? My goodness! (6)
I believe the answer is:
crikey
'my goodness' is the definition.
(both are expressions of surprise)
'protest about the president?' is the wordplay.
'protest' becomes 'cry' (as in a cry of protest).
'about' means one lot of letters goes inside another.
'the president?' becomes 'ike' (nickname of Dwight Eisenhower).
'cry' placed around 'ike' is 'CRIKEY'.
(Other definitions for crikey that I've seen before include "Good heavens!" , "by George" , "Cor blimey!" , "Gosh!" , "Good Lord!" .)