America backed Biden-Trump leadership election? At first, it's not obvious (6)
I believe the answer is:
subtle
'not obvious' is the definition.
'america backed biden-trump leadership election? at first' is the wordplay.
'america' becomes 'us' (abbreviation for the United States).
'backed' says the letters should be written in reverse.
'at first' suggests taking the first letters.
The initial letters of 'biden trump leadership election' is 'btle'.
'us' written backwards gives 'su'.
'su'+'btle'='SUBTLE'
'it's' is the link.
(Other definitions for subtle that I've seen before include "Indirect, difficult to detect" , "Slight and difficult to analyse amid bustle" , "Understated, fine" , "Discreet" , "Delicate and understated" .)