Come si traduce in italiano?
but he should have known the powers that be, would never let it go at that. Even Obama answers to the powers that be.

Il contesto:

We created Al-Qaeda and I have no doubt that the CIA helped create what we know today as ISIS. The military industrial complex knew that once we went into Iraq, we would never leave. I applauded Obama for pulling soldiers out of Iraq, but he should have known the powers that be, would never let it go at that. Even Obama answers to the powers that be.

Question

Come si traduce in italiano?
but he should have known the powers that be, would never let it go at that.  Even Obama answers to the powers that be.

Il contesto:

We created Al-Qaeda and I have no doubt that the CIA helped create what we know today as ISIS.  The military industrial complex knew that once we went into Iraq, we would never leave.  I applauded Obama for pulling soldiers out of Iraq, but he should have known the powers that be, would never let it go at that.  Even Obama answers to the powers that be.

Answer

Ho introdotto un altro verbo: /deve rispondere/ invece di /rispomde/, in quanto
il significato e` piu` chiaro in italiano.
Versione ancora piu` forte:

-- Anche Obama {obbedisce, si piega} ai poteri forti.

Answer

... ma avrebbe dovuto sapere che i poteri forti non glie lo avrebbero perdonato.
Anche Obama deve rispondere ai poteri forti.
'Powers that be' = 'poteri forti' (I think so)
(Trafficanti  di armi da guerra?,  potenti della finanza?, imprenditori petroliferi?)