Why do gun laws work in every other country then? To varying degrees of course. Or is it not the gun laws that is the defining difference?
They don't necessarily. You have to compare violent crimes per capita in each country with the varying laws. You cannot just compare gun crimes but all violent crimes. Other countries that have very strict laws may have more violent crime committed with knives or some other weapons. I haven't seen a map or chart that shows this but there are many articles on the internet.
This shooter was stopped by an armed citizen. So if he had gone into the church and did what he did, and there were no armed citizens--how many would he have killed? The only way stricter gun laws will work is if we can make darn sure the shooters aren't able to get guns and I don't think we can do that.
What I do think we have is a mental health problem. There has to be a happy medium between locking up anyone and everyone suspected of mental illness and not being able to get anyone the help they need. If family and friends report someone acting erratically, it shouldn't be so hard to get them seen by a mental health provider and in-patient at least until they are deemed safe to themselves and society.
Now, I have read a couple of articles that have corrected some things since the shooting. One, he was not dishonorably discharged, it was listed as a bad conduct discharge. I know nothing about the different levels of discharges but one article says this is not a felony (not that it is recognized that way in every state anyway) so would not have stopped him from getting a gun. He was discharged and served time due to an attack on his then wife-guessing that wasn't a felony either. Rather than spending time in jail maybe he should have been mentally evaluated then?
He was denied a gun permit in Texas, so doesn't seem that permits are necessarily the answer.
As far as the question in the OP. Well, its really up to the congregations in smaller churches like this one. They have to decide what they are willing to do. Our church is pretty much considered a "mega" church. There is no way the ushers can watch anyone new as there may be 50-100 new people on any given Sunday. Our sanctuary is very theater like and once the music starts (which is loud) its dark in there. Some of the things that have been done are that our ushers (really not ushers but volunteers each week) walk any late comers in and using a pen light, show them to a seat. We have a lot of police officers in our congregation and they have volunteered to take turns being in the hallway out front during services. There are 4 doors into the sanctuary and they close all but one once the service starts. The volunteer officer "greets" people at that door. But even this isn't fail safe. They can't lock the other doors and as our sanctuary is round at the back, there is a curve in the wall that makes it impossible to see every door. But, there are volunteers at the coffee shop out there and at the guest services desk so anyone coming in will be seen. Children and babies that are in their classrooms or in the nursery are all behind very secure, locked doors that lead into an entry way to another set of doors and then down a hall way, so that's a big relief at at least.
Churches are pretty much sitting targets but hopefully as many as possible will be able to come up with something that will keep the church safe but also keep them welcoming to anyone and everyone that truly wishes to attend.