Jordan as created at the end of the British Mandate. Which is to say, including the West Bank. There has never been a state with its border at the Jordan, and the populations on either Bank are one people. The answer to the question of why anyone ever designed a country so short of water as Jordan is, is that no one ever did.
The creation of a Palestinian State in the West Bank would be the end of the Hashemite Kingdom: the pressure for incorporation into that State would be irresistible. That, rather than the destruction of Israel, would be the great national aspiration. And then, following its rapid and its largely (if not entirely) bloodless achievement, that would be the great national triumph.