My letter to my congresswomen is posted below. This has been a tough call.
Dear Rep Esty,
Thanks for your invite to tomorrow's Town Hall. I can't make the event, but I write to urge you to support the deal. I'd be deceiving myself, and you, if I denied my misgivings; there's no question the deal has flaws, and that it carries risk, as the President has acknowledged. Could we have done better? Perhaps. There's no logic or reason to believe that the alternative, its rejection, will move us no closer to our goal of a non-nuclear Iran. Rejection, as argued by many observers, has a high likelihood of producing an escalation of Iran's effort to build a bomb, and the inevitable (and likely unsuccessful) military response to that effort that will follow.
We don't have to like Iranian regime, or even trust it, to reach this agreement. We have follow our own best self interest. For now, this is the best we are going to do.