The children of Israel again did that which was evil in the sight of Yahweh; and Yahweh delivered them into the hand of the Philistines forty years.
There is a missing note here.  Whereas, in the introductory paragraph for each of the other judges, there is the record of Israel's distress leading to their cries unto God for deliverance.  Nothing like that occurred here.  The encroachment of the Philistines was benevolent enough in character that Israel seemingly consented to it, not realizing the awful danger of losing their identity by an amalgamation with the Philistines.