What was the greatest foreign policy victory for the Carter Administration?
http://www.google.com/search?q=president+carter+foreign+policy&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA
The first four links in these results seem to be most promising for answering your question.
=)