Conversation so far:
When did Robin Cook become foreign secretary?
With the election of a Labour government led by Tony Blair at the 1997 general election, Cook became Foreign Secretary.
what did Cook do as foreign secretary?
Cook announced, to much scepticism, his intention to add an ethical dimension to foreign policy.
did Cook help in any changes while in his position?
Cook's term as Foreign Secretary was marked by British interventions in Kosovo and Sierra Leone.

Question: was he successful in doing so?
Self-contained rewrite: was Cook successful in the British interventions in Kosovo and Sierra Leone?