Angus King actually said...

I don't see it--how it's possible to argue that the sanctions will be stronger if this deal is rejected.

If the Iranians begin to misbehave after the limitations in the current agreement expire, they're misbehaving from an incredibly higher base...

the real question then becomes--is, What is the alternative?

The other aspect that makes me uncomfortable are the more immediate effects of empowering a state that should still be a renegade state.