Meanwhile, Johnson keeps trotting out the same phrases over and over (3,3)
I believe the answer is:
pro tem
'trotting out the same phrases over and over' is the definition.
I can't tell whether this definition defines the answer.
'meanwhile johnson keeps' is the wordplay.
'meanwhile' becomes 'rote' (I can't justify this - if you can you should give a lot more credence to this answer).
'johnson' becomes 'pm' (prime minister Boris Johnson).
'keeps' means one lot of letters goes inside another (inserted letters are kept inside).
'rote' going into 'pm' is 'PRO TEM'.
Can you help me to learn more?
(Other definitions for pro tem that I've seen before include "For the time being (Latin abbreviation)" , "Temporarily" , "Informally, for the time being" , "not indefinitely extended" , "For the present" .)