American’s crisp about two Republicans, you heard, in tweet (7)
I believe the answer is:
chirrup
'tweet' is the definition.
(I've seen this before)
'american's crisp about two republicans you heard' is the wordplay.
'two republicans' means two replacements for 'republican'.
'american's crisp' becomes 'chip' (a crisp to a British person is called a chip in US).
'about' indicates putting letters inside.
'republican' becomes 'R' (abbreviation).
'republican' becomes 'R' (abbreviation).
'you heard' becomes 'U' (homophone of 'you').
'r'+'r'+'u'='rru'
'chip' going around 'rru' is 'CHIRRUP'.
'in' is the link.
(Other definitions for chirrup that I've seen before include "Make high-pitched sounds" , "Noise of a small bird" , "Trill" , "Tweet" , "Bird's sound" .)