Four unlikely premises support the claim America and our allies struck a worthwhile deal with Iran.

First, that there is reason to trust an adversary that has repeatedly proven itself untrustworthy. Second, that our permanent concessions are worth our temporary gains. Third, that a U.S. administration last seen equivocating over a “red line” it created for Syria won’t go wobbly if Iran violates the pact. And fourth, that Russia and China, which always try to blunt any pressure on Iran, won’t stand in the way of reimposing sanctions or other consequences.

Seen from Iran’s perspective, these are four good reasons Tehran casts the deal as a triumph.

About 18 months ago, the two sides couldn’t agree on terms that were strikingly similar. Iran wanted relief from international sanctions. Its counterparts (the U.S., Britain, France, Germany, Russia and China) wanted Iran to stop enriching uranium to a purity level of 20 percent, a key threshold to creating the material for a nuclear bomb.

It was only about six weeks after those talks broke down that perhaps the most stringent economic sanction on Iran, a European Union embargo on Iranian oil, took effect. That sanction and related U.S. measures have cost the country an estimated $4 billion to $8 billion per month. Rampant inflation followed.

Yet just as Tehran was feeling the pressure, we decided to ease up.

In one superficial way, this deal is better than the one contemplated in May 2012. Then, Iran was asked merely to stop enriching uranium to 20 percent. Now, it must dilute its stockpile of 20 percent uranium to a lower level.

The problem with considering this an actual concession goes beyond the implicit authority it gives Iran to continue enriching uranium to the 5 percent threshold, a recognition we rightly refused last year.

It also requires one to ignore the process of uranium enrichment. The vast majority of the work required to enrich uranium from its natural state (less than 1 percent pure) to weapons-grade (at least 90 percent pure) comes in getting to the 5 percent threshold.

If that sounds counter-intuitive, that’s because enrichment is not a linear activity. It takes far more time and effort to get to 5 percent than to go from there to 20 percent. Going from 20 percent to 90 percent takes even less.

To gain a little time, as well as some inspections the International Atomic Energy Agency has already declared insufficient, we are giving Iran access to billions of dollars from its now-frozen reserves. We’re also easing sanctions on trade in some oil products, as well as airplane and automobile parts. Any money or materials entering Iran from that trade can’t be clawed back.

There is another faulty premise underlying this deal: the notion that the only alternative to striking this deal, according to an arbitrary non-deadline, is war.

It seems equally probable that negotiating ourselves into a position of weakness will only embolden Iran to keep moving toward a point of no return. As long as the harshest sanctions were still at work, and the parameters of a deal yet to be set, there was the chance Tehran would have decided to make bigger, more permanent concessions.

And that would have meant more reason for optimism for all of us who hope for a peaceful resolution to this deadly dilemma.