Nowadays, party has to improvise (2,3)
I believe the answer is:
ad lib
'to improvise' is the definition.
(I've seen this before)
'nowadays party' is the wordplay.
'nowadays' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'party' becomes 'lib' (abbreviation for Liberal, uk political party).
'ad'+'lib'='AD-LIB'
'has' is the link.
(Other definitions for ad lib that I've seen before include "with no forethought" , "Improvised" , "Made-up" , "Off the cuff remark" , "Speak unprepared" .)