Surely you don't mean 100% of all Israel, do you?
Giving the Palestinians a homeland is not going to solve the problem. It's known what the objective of the Palestinians (and most Muslims in the area) is -- to drive the Jews OUT.
Israel will have to act. Having gone on record as "officially" endorsing a Palestinian homeland, America will have a stake in it, and as self-appointed world's policeman, will directly insinuate itself into the situation. Against Israel.
It's just following a + b + c. Connecting the dots.