Silke boils down Stratfor's analysis: Israel you better behave or the US will replace you by Turkey. It's an empty threat. Israel suits the American need of balancing the western Middle East better than Turkey every could, for one reason - due to its demographics it is, reliably, at the historical and practical limit of its power projection.
The Turks have dominated the region for hundreds of years. The last thing the US wants to do is empower a resurgent Islamist Turkey, with an economy that dwarfs the rest of the Middle East (17th largest in the world), to reassert itself. That creates the exact conditions the US wants to avoid - a regional hegemon that can consolidate landmass and threaten US interests.
The US needs Israel to contain Egypt and Syria, and protect the Jordanians from both. In the American playbook, Turkey would be useful as a counter to Iran (and Russia), but it does not seem eager to take on this role. The Turks understand that Iran is currently driving the geopolitics of the Middle East - incidentally, driving out American power. The winning position is to act as mediator between the Arabs and Persians, leveraging their mutual antipathy to assume influence over both.
Fundamentally, no one is challenging Turkish sovereignty, the way multiple states and international institutions are with Israel. The Turks are secure and growing, if slowly. They don't depend on the US the way Israel does, by which I don't mean aid, but the broad industrial base necessary to ensure national survival in wartime. They can afford to (re)build their own empire on their own terms.
By the way, the same goes for Egypt and Syria as well. Both nations are at historical lows, geopolitically. Capability drives intent: 70 million starving Egyptians may be fighting for bread today, but 70 million well-fed Egyptians can be raising an army tomorrow.
Israel is a lamb among sleeping lions.
There is no replacing Israel in the US alliance system, and any such talk is rubbish. Obama wants regime change in Jerusalem to a government more pliant to American sensitivities; no one is seriously contemplating displacing Israel. An Israel without a great power backer will not shrink its ambitions, but will use its operational freedom to boldly assert itself in ways it is currently constrained from doing, the way it did in '67 and '73, when Israeli tanks were positioned on the gates of Damascus and Cairo. The Americans want that kind of capability, but only under their control.
The last American President to make similar demands of Israel was Clinton; Netanyahu faced off with him and lost, bringing Barak to power. We'll see.