Isley Brothers vs. Michael Bolton
This case was originally based on five unprotectable elements. The most important of these was obviously the title phrase that is melodically similar, even if just moderately so. The matching of the words was surely a strong factor. And they added four other subtle similarities.
My analysis shows third party examples demonstrating how usual is the extent of the melodic similarity between Isley Brothers' and Michael Bolton's song. On the other hand I also show one subtle detail (a rhythmical variant) that was probably inspired by the Isley Brothers version directly. This subtle detail on the other hand it is just weakly amplifying the extrinsic similarity.
This case was a key reference during the Blurred Lines case too. 17 years after the Supreme Court ruling (24 after Federal Court ruling) I've found a prior art song that must have "inspired" the Isley Borthers. The similarity is striking both extrinsically and intrinsically. The key detail of the original case (the title phrase) is shown not to be original to Isley Brothers.
This blog entry is the first report of this finding.
My judgememt: no infringement. Even without considering the prior art example - but a close one. The direct inspiration is probable.
Third party prior song judgement: this is infringement, may be unconscious tough.