House a witty new Democrat enters, sure of success (4,3,3)
I believe the answer is:
home and dry
'sure of success' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'house a witty new democrat enters' is the wordplay.
'house' becomes 'home' (homing is a kind of housing).
'witty' becomes 'dry' (both can mean humorous).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'democrat' becomes 'd'.
'enters' means one lot of letters goes inside another.
'n'+'d'='nd'
'a'+'dry'='adry'
'adry' enclosing 'nd' is 'anddry'.
'home'+'anddry'='HOME AND DRY'
Can you help me to learn more?
(Other definitions for home and dry that I've seen before include "Definitely safe or successful" , "Having achieved one's objective" , "Successfully arrived at the end of a difficult enterprise" , "In a position to reach a goal without much further difficulty" .)