I think the best lock for a screen door is any lock that would cause someone trying to break through it to make enough noise that would then possibly dissuade the person breaking in from continuing. With that said, when I had my alarm system installed, and the installer and I got around to talking about screen doors, and door locks, the basic message I got was this: If there is someone determined to get into your home, and they are confronted by a locked screen door and a locked wooden door behind it, if that someone is a knowledgeable burglar, getting through any screen door and any door behind it, is just a matter of seconds. And, if there's an easier way in (window, etc), they'll take the easy way in and bypass the door.
With that said, an unskilled burglar won't want to draw attention to themselves, so if its too visible and/or noisy a task to get through your door or windows, they'll try someone else's house where they can work more privately. Bottom line, a nice screen door with a good lock may make you feel more secure, but don't delude yourself into thinking that a locked door can actually stop someone who's motivated and skilled from breaking in.
Stacy90802 has a good answer. To add to that, I have seen some doors that are solid and have some screening that have wrought iron strips in front of the screen area. That would be a little safer.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.