How likely is an Iran deal?

If I were Iran, I would view the current period as a golden opportunity for a nuclear deal.  The senate Republicans and Netenyahu have presented the Iranians with something of a win-win situation if they have any intention at all of making a deal.  For one, if the Republicans are able to scuttle a deal that the Obama administration signs onto, then that may well cause the sanction resolve of China and Russia to weaken.  If the US isn't willing to negotiate in good faith then how can Iran be faulted?  So they might be able to sign up for a deal, and when the Republicans vote it down they can resume previous activities while blaming America.  On the other hand, if the Republicans aren't able to scuttle the deal, then the Iranian moderates have some serious political cover.   They can say: Look how good this deal was for us, Netenyahu hated it so much that he breached normal diplomatic protocol to give a speech in the US Senate.  The Republicans hated it so much that they wrote an unprecedented letter to the Supreme Leader that was resulted in various political commentators calling them traitors.

Any Iran deal is bearish for oil over both short and long time horizons.  If Iran actually became a normal country, their production might dramatically increase over the long term.  Today they export 1-1.5 million barrels per day.  But they are only producing 3 or 3.5 compared to 5.5 million per day which they produced in the 1970s before the revolution.