Over and over, this same argument comes up. It is even today as it was then.
Today, the Palestinian Arabs, along with much of the rest of the Arab world, lay claim to the same land that the Israelites and Ammonites were arguing over in the time of Jephthah. The Ammonite king asked Jephthah to give them back their land that the Israelites had taken as they came out of Egypt, but the answer from Jephthah was that Yahweh had given the land to them. Why should they give it back?
Even looking on Israeli websites today, there is a harkening back to the story of Abraham and to God (Yahweh’s) promise to give the land of Canaan to Abraham’s descendents, to which Israel lays claim as Yahweh continues his covenant from Abraham to Isaac and Jacob.
There is, inherently, a challenge to the Ammonites when Jephthah replies to the king of the Ammonites. Jephthah says:
“Now since the LORD, the God of Israel, has driven the Amorites out before his people Israel, what right have you to take it over? Will you not take what your god Chemosh gives you? Likewise, whatever the LORD our God has given us, we will possess.
Judges 11:23-24
So Jephthah asks the king of the Ammonites: Is your god Chemosh greater? Or is Yahweh greater? The answer is clear. We own the land. Yahweh is greater.
And this is the same argument that is ongoing today.