The obvious answer to this question is yes.  Even the most despised client deserves representation.  This is especially true in criminal cases.  The ethical rules make it clear that lawyers are not morally accountable for the actions of their clients.  This is so that even unpopular litigants can find representation.  But the question is more complicated when the client is an individual or entity controlled by a hostile foreign government.

The Mueller investigation has highlighted some of the potential problems for lawyers who choose to represent hostile foreign governments or individuals and entities connected with those governments.