Dan Drezner thinks hawkish critics have been too quick to reject the interim deal with Iran. He suggests an alternative:

Now say you announce that despite your reservations, you’ll support the Obama administration’s steps towards peace provided the necessary security guarantees are procured, etc. In this universe, if the deal falls through, it’s on the Obama administration, and you get to shake your head sadly and cluck about how you should have known better than to trust them. If the deal succeeds but a comprehensive deal fails, that’s also on the Obama administration, nothing has been lost, and you look like a sober statesman. Finally, if a comprehensive deal really is reached, you can oppose it then. Indeed, your opposition will be bolstered by the fact that you supported the interim negotiations, suggesting that you’re not opposing diplomacy like a knee-jerk automaton.

This overlooks that opposing diplomacy with Iran is a matter of pride for many Iran hawks, so it really makes no difference to them if the deal is a short-term one or not. Flatly rejecting even an interim deal is how they establish that they are more hostile to Iran than everyone else, and they want to demonstrate this because they think it is laudable to be as hard-line as possible on this issue. As for looking like “sober statesmen,” this is not very important to most of the deal’s detractors. If the choice is between being seen as reasonable or being seen as relentlessly hard-line, I suspect that many Iran hawks would prefer the latter. Put another way, John Bolton does not want to “chill,” and sees no reason to do so.

Drezner may be right that Iran hawks would retain more credibility with everyone else if they held their fire for a later, comprehensive agreement, but among other Iran hawks they would lose credibility if they endorsed any deal with Iran. So they denounce the current deal, and they will denounce future agreements in the same terms, because they really are opposed to diplomatic engagement with Iran all together. Besides, Iran hawks have raised the bar so high on what it means to be “tough” on Iran that they are stuck defending ludicrous positions that they were compelled to adopt to confirm their status as a hard-liner.