The old saying that goes: Those who know don’t say. Those who say don’t know.
It is a fitting response to all the public speculation about what will come out of the Iranian nuclear negotiations that are supposed to be completed by November 24.
Prime Minister Benjamin Netanyahu as gone into overdrive in messages to leaders trying to hammer out a deal with Tehran: the United States, Britain, France, Russia, China, German and the European Union.
His latest message focuses on the nine-point plan offered by Iran's supreme leader for the eradication of the Jewish state. That accompanied the Grand Ayatollah's tweet saying, "This barbaric, wolflike and infanticidal regime of Israel…has no cure but to be annihilated."
Could that be what is really behind his nuclear program? Bibi Netanyahu seems to think so and so do many others.
We don't know what a nuclear agreement with the Iranians will look like or whether there will even be one this month, but this much you can count on: whatever it contains Netanyahu and his Republican allies will oppose it.
They've already begun their campaign. Republican leaders in Congress have served notice that they don't trust Iranian promises – who does? — and want to see more sanctions, not fewer, until there is solid proof that Iran can't and won't build a nuclear weapon.
The White House has said any agreement with Iran does not have to be submitted to Congress for approval, but Congress wants to see it anyway and hold hearings, and it has a lot of leverage.
Not all of this is about the substance of any agreement; there's also an equal if not greater dose of partisan politics at work here.
Republicans can be counted on to oppose any agreement negotiated by the Obama administration because their top priority is denying this president any foreign policy achievements.
That's not to say it doesn't deserve close scrutiny and a healthy dose of skepticism over Iranian intentions and trustworthiness.
As for Netanyahu, you can count on him to oppose any agreement short of white flags flying over the nuclear ashes of Tehran, and even that is not guaranteed.
Read the rest of my analysis of why any Iran deal could be DOA on Capitol Hill in my Washington Watch column.