If the United States scuttles Thursday’s deal, Ali Vaez, senior Iran analyst at the International Crisis Group told me, Rouhani and Zarif will “be totally discredited, marginalized. That would be the end of Rouhani’s attempt at talks to resolve this peacefully.” Rand Corporation Iran expert Alireza Nader added that, “If everything collapses and Rouhani has nothing to show for his efforts, the balance may go toward conservatives and ultra-conservatives and they can make it hard for him to go back to table.”

Finally, there’s a third, less well-appreciated flaw in Netanyahu’s argument. He assumes that after walking away from the current deal, the United States can “ratchet up the pressure on Iran.” In fact, the pressure will likely go down.

Yes, Congress can pass additional sanctions. But more American sanctions alone won’t have much effect. After all, the United States began seriously sanctioning Iran in the mid-1990s. Yet for a decade and a half, those sanctions had no major impact on Iran’s nuclear program. That’s largely because foreign companies ignored American pleas to stop doing business with the Islamic Republic.