It may not be just political
George Will makes a case that there are other motives playing here. Perhaps, perhaps not.
In the end, it's not very realistic to expect Israel to give up so much territory so that it's indefensible when it has been through so much turmoil in it's brief history. Israel would only be something like 7 miles wide at one point under the 1967 borders. They have been attacked several times in those few decades, so it's not exactly easy to trust those same people not to do it again.