The basic contention for paladins is not that they are smiters of evil, but that they are also the defenders of order. Note that I said order and not law. Modern law is ironclad, we have specific definitions of crimes, require proof of those crimes, and punish those found guilty according to set standards based on the crime committed. Medieval law had very little of these things. There was no presumption of innocence, no due process of law, no rights to a quick and fair trial, and the punishments usually far outweighed the crime. Power was more important than law. Order was the status quo, not law. Making paladins uphold the standards of the modern code of law is what causes problems. DM's should establish a code of conduct for their campaigns, and hold the paladin to that. It would solve many problems.