Agressive Golden

Question
We have a male Golden (neutered) who is about 4 years old.  We got him when he was about 9 months (at which time we neutered him - enough dogs out there needing homes) - we were his 3rd home and I don't know his previous experiences.  When we got him, we took him to a trainer due to some aggression/submissive urination issues.  He would bare his teeth if he didn't feel like listening and often before we would reward him, he'd urinate.  The trainer used a similar method to one I had read - keeping him on a leash and tugging when he would not listen and continuing to tug each time harder until he listened.  This resulted in his no longer warning us with a Grrr but instead snipping and eventually he bit when correcting him while at class - not hard but it certainly gave me a scare.  

We continue to "reward him" to help with the submissive urination issues to boost his confidence which is working but obviously the "traning" had failed with regard to his aggression.  In retrospect it was obviously not the right training our dog needed.  Although we completed the "training," he is still aggressive.  I am afraid to have him around anyone - though he does not display it often, it still concerns me.  When he doesn't feel like doing something, he bares his teeth and will snip.  He wants to be the dominant whether he is on the couch (a "no"), told to lay down, etc.  I don't know what else to do with him.  We have tried other training methods... but he still shows aggression every now and again.  He is a great dog the other times and usually listens very well. I am just at a loss for what to do with him... I am hopeful you have some suggestions.

Answer
Some dogs seem to be born more dominate than others.  They start out when they wake up from a nap, they head over to mother and push the other puppy away from the first nipple they come to.  At weaning time, they are first to the food dish.  When anybody comes near the whelping box, they push their way to the front.  In the hands of a strong leader, these dogs can be trained to do wonders.  Some of them react very poorly to harsh training methods.  Likely he lost his first 2 homes because people couldn't handle him with the methods they were using.  

I don't know that I can help much either.  Perhaps there would be enough at http://www.dogbreedinfo.com./topdogrules.htm to help.