It's true that Joe did a lot of things that he shouldn't have done which is what led him to the theoretical situation he is in. But for the sake of argument, let's say that's what Joe did...
First of all, Joe should either keep hitting "Ron" until he is no longer a threat or try and make a break for it. Ron could still attack him with his hands, or he could go for a weapon. As long as Ron is still standing in front of Joe, he is still a threat.
I'll have to disagree with what others have written here. At least in the state of California, Joe is justified in hitting and kicking Ron. Ron pursued Joe from the parking lot into the store, he verbally threatened to kick Joe's ass (which is technically an assault, but not battery until he hits Joe), he was walking at Joe with his fists clenched, and he continued closing the distance even after Joe apologized. Ron had the intent, means, and opportunity to cause harm to Joe. Joe feared he was going to be attacked, so he defended himself. As long as Joe uses reasonable force to stop Ron (no kicking Ron once he goes down, no bashing his head with an object, etc.), he should be ok. Joe may still get arrested initially (after all, Ron will say he got hit first), but he should be able to defend himself in a court of law.
Since it happened in a grocery store, there would probably be witnesses who saw and heard Ron threaten Joe, saw Joe apologize, and saw Ron with his fists clenched continue to approach Joe even after the apology. This will help Joe's case because it's no longer a case of "he said, he said."
So when Joe gets on the stand, he simply says, "Ron followed me from the parking lot into the store, and he threatened to kick my ass. I tried apologizing but he kept coming at me with his fists clenched. Once he got within a few feet of me, I was afraid he was going to attack me so I defended myself."
If Joe did nothing and waited for Ron to attack first, it's certainly clear who made the first move - but what if instead of punching Joe, Ron attacks with a knife? Or he pulls a gun out of his back pocket? Or Ron sucker punches Joe, Joe goes down, and then Ron starts kicking Joe in the head? Here in California from time to time you read or hear about shootings that started with a road rage incident. Joe would be crazy to just let Ron attack him first because he has no idea what kind of attack it will be.
In the end, it was reasonable for Joe to believe Ron was going to carry out his threat in some manner, so Joe was justified in defending himself.
[This message has been edited by raptor_prime (edited 07-25-2004).]