Ronald in charge after short time, how idiotic (7)
I believe the answer is:
moronic
'idiotic' is the definition.
(thesaurus)
'ronald in charge after short time' is the wordplay.
'ronald' becomes 'ron' (I've seen this in other clues).
'in charge' becomes 'ic'.
'after' says to put letters next to each other.
'short time' becomes 'mo' (slang abbreviation for 'moment').
'ron'+'ic'='ronic'
'ronic' put after 'mo' is 'MORONIC'.
'how' is the link.
(Other definitions for moronic that I've seen before include "Omicron (anag) - stupid" , "ROM coin (anag.)" , "Mindless" , "Foolish" , "really stupid" .)