Almost inevitably, the latest IAEA comments regarding the visit to Iran are being framed as yet more evidence of Tehran’s defiance and duplicity.
The IISS is amongst the first to jump to conclusions with the headline "What is Iran hiding at Parchin?"
Mark Fitzpatrick writes that inspectors wanted to visit  Parchin because "US officials suspected [it] might be used for high-explosive tests related to nuclear weapons development".
Thus, Tehran’s refusal to allow access must be because there is something to hide, right?
Well, there may be another explanation. As Tehran Bureau points out,
According to the Safeguards Agreement, the IAEA can visit only those locations declared to be nuclear sites - which does not include Parchin - and has no legal right to demand entry to other sites.
So Iran may have simply been sticking to the letter of the law and asserting some measure of sovereignty.
But still, if they had nothing to hide, why hide it?
Well, it seems Fitzpatrick has provided one possible answer himself -
The IAEA had been led to believe they would have access to the Parchin, [...] But hardliners in
Tehran prevailed over those who wanted to demonstrate some flexibility"
In other words, one political opinion prevailed over another.
That the nuclear debate is as robust inside Iran as outside is no secret. Nor is it news that a large number of very vocal politicians consider this nuclear row to be nothing more than a pretext for interference in its affairs.
That some politicans would insist on strict adherence to existing agreements would therefore seem pretty much within bounds.