Bummer is going to tell Israel to give up half of Jerusalem to the Moose, and Israel is going to tell him nothing doing.
I think he assumes that Israel will refuse the imposed plan. The US will then simply fail to veto UN Security Council sanctions/embargoes against Israel. As the situation then deteriorates, an international force will be ordered in to “keep the peace”. This could start as a “human shield” variety, consisting of UN troops. If, as is likely, the Israelis remain intransigent regarding Jerusalem, a more potent force, like the NATO group in Serbia, would be deployed. The key for the Administration is not to move so fast that outrage in the US and in the Congress in particular shuts him down. He’s got to demonize our erstwhile ally in the minds of as many Americans as he can. That will take some doing and some time.