Urges Republican to be refused cases (4)
I believe the answer is:
pods
'cases' is the definition.
(pod is a kind of case)
'urges republican to be refused' is the wordplay.
'urges' becomes 'prods'.
'republican' becomes 'r' (abbreviation).
'to be refused' indicates named letters should be taken away.
'prods' with 'r' taken away is 'PODS'.
(Other definitions for pods that I've seen before include "Pea-jackets" , "Pea cases" , "some seals" , "From enclosed cabins" , "schools of whales?" .)