From what I can tell, nothing in the Iran deal prevents us from going to war with Iran. In fact, the deal itself, if violated by Iran, may even make it easier for us to go to war with Iran. It sets up the perfect and justifiable pretext for war if Iran violates the deal. The international community would likely support bombing Iranian nuclear sites under that scenario. Such a violation would at least set up the justification to re-impose the crippling sanctions that forced Iran to negotiate in the first place. Moreover, the deal, if not violated by Iran, dramatically slows and montitors Iran's capability of producing a nuke.
If we walk away from this deal, we will not be able to re-impose the brutal sanctions Iran had been subjected to. The other country-parties to this agreement only agreed to go along with those crippling sanctions on Iran because they were assured that these sanctions were necessary to bring Iran to the table to negotiate.
Walking away from the current deal would make such assurances hollow in any future attempt to get cooperation from other countries to re-impose sanctions on Iran. What would be the US argument to these countries to re-impose the same level of sanctions? To get a better deal? Our credibility would be shot. We would also lose the ability to inspect and monitor Iran's nuclear enrichment.
In the absence of this deal, Iran would likely go on subjected to weaker sanctions than it is now and could develop a nuke within a year. But without a violated deal in place to point to, there would be no strong pretext for a US strike on Iran even if we strongly suspected that Iran was developing a nuke. Getting cooperation from the international community to bomb or re-sanction Iran would be a much tougher sell without a clearly violated deal to point to. Justified or not, under that scenario, our case for war would sound a lot like our now-unjustified case for invading Iraq to most potential allies.
So the choice is not, from what I can see, the Iran deal or war with Iran, as so many on the left contend. Nor is it the choice between trusting or not trusting Iran, as the right condends.
The choice is a between a unified international front against a monitored Iran under a clearly-defined deal or America going it alone against and an umonitored Iran under no deal.
Where am I wrong?