Marco Rubio wants us to know that his ideas for diplomacy with Iran are still terrible:

Tough sanctions are exactly what has brought Iran to the table now, and tightening sanctions as we engage diplomatically affords us the opportunity to apply further pressure and force Iran’s leaders to choose between regime survival and a nuclear weapon [bold mine-DL].

This is very confused. Imposing additional and tighter sanctions will undermine negotiations by making the Iranian side assume that the U.S. is never going to provide any sanctions relief. As the Iranians would see it, tightening sanctions would mean that the U.S. had responded to conciliatory gestures with even more punitive and hostile measures. Tighter sanctions punish those in Iran that might be willing to make a deal, and reward those that would just as soon see diplomacy fail. Then again, one has to assume that this is the point of pushing for ever-tighter sanctions no matter what: to kill off the possibility of a diplomatic solution and continue to strangle Iran economically.

The fact that Rubio thinks that this threatens “regime survival” confirms that he believes that enough sanctions can be imposed on Iran so that the government will eventually fall. There is no reason to think that inflicting additional suffering on the Iranian civilian population will result in the collapse of the regime, so the regime won’t face this choice, but as long as Iran hawks such as Rubio keep thinking this there is much less chance that sanctions will ever be lifted. The choice the U.S. faces is one between perpetuating a cruel and unnecessary sanctions regime or agreeing to end it in exchange for Iranian commitments on the nuclear issue. Rubio favors the former, and he clearly doesn’t care what effect this has on diplomacy with Iran, which should tell us everything we need to know about why his recommendations should be ignored.