Hello Englishman:
I remember the Woodward case quite well. The press here in the United States had much to say about the incident and trial, and there was more than a little criticism of the parents' seeming lack of involvement with raising their children. In particular, there were a lot of hard feelings towards the child's mother for persuing money that the family didn't really need and spending more time on her career than caring about her offspring. A lot of people had a hard time believing that Woodward would do anything, intentionally or not, to harm a child. A few thought that there was some cover-up of wrongdoing by someone other than Woodward.
Since an establishment of intent is required for a murder conviction, I can understand why the judge acted to reduce the charge. A side issue is the release of Woodward immediately after the trial; she had served nine months and some thought that this wasn't long enough.
Personally, I think the judge acted properly in a hard case.
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On occasion, although not very often, a judge will downgrade or discard a jury verdict of guilty. Also, it is not uncommon for a judge, usually via appeal, to reduce monetary awards established by jury verdict.
I cannot recall any instance of a judge discarding a verdict of not guilty. This may not be allowed.