Confirm or support (6)
I believe the answer is:
uphold
I believe this is a double definition.
'confirm' is the first definition.
(I know that uphold is a more specific form of confirm)
'support' is the second definition.
(I know that uphold is a more specific form of support)
(Other definitions for uphold that I've seen before include "Sustain and endorse" , "'Support, the law say (6)'" , "Of appeal court, endorse earlier decision" , "Champion" , "'Support, a court decision, say (6)'" .)