Let's say for a moment that there was a big meeting at the prosecutor's office. Cops, CSIs, prosecutors, lab types, etc. Everyone sat around and said "this is the best we've got. It's never going to get any better." I've been in those kinds of meetings. At that point, everyone looks to the man (or woman) with his name on the front door, and he makes the call. It's either go with what you've got, or wait and hope for better evidence.
But "go with what you've got" has to include recognizing what you've got ... and what you DON'T got.
In this case, they had a dead kid. That she was dead was obvious. Beyond that? Nada ... zip ... zilch ... zero. Without anything to show
how she died, they couldn't really even show that the death was a homicide, as opposed to an accident or a health-related incident. An experienced, career prosecutor on the verge of retirement SHOULD have learned that the essence of the American system is that the government must prove its case beyond a reasonable doubt.
How do you prove ... beyond a reasonable doubt ... that Casey Anthony murdered her child, when you can't even prove there was a murder? In fact, you can't even prove there was a homicide (which, BTW, is NOT the same thing as "murder").
I spend a lot of time ranting against what I call prosecutorial overreach. Usually, it takes the form of piling on absurd charges with malicious intent, to either break the defendant financially (and perhaps psychologically) or in the hope that out of the whole list,
something will surely stick. It sucks, and it's wrong. People who do wrong should be arrested, tried, and convicted. But along with that goes the supposition that a person gets charged with what he or she might actually have done, not a laundry list of fantasy charges that only a contortionist could see relating to the actual facts of the incident.
This was such a case. Here, though, I don't think it was done out of malicious intent. I think it was done out of stupidity. They were all convinced that Casey Anthony
had killed her child, so they forged ahead on the assumption that they had to try her for that using whatever evidence they could scrape up. I seriously doubt the arcane notion of charging her based on what they thought they might be able to prove ever occurred to them.