By contrast to President Obama’s loud public support for the P5+1 nuclear deal with Iran, Iranian Supreme Leader Ayatollah Ali Khamenei has been seen as extremely cautious. Indeed, he hasn’t officially gone “on the record” as being for the deal.
Not that he’s been completely silent on the matter, mind you. Khamenei loudly endorsed the negotiation process throughout, and in the wake of the deal his comments were largely positive, even if he downplayed the impact it would have on US-Iranian relations.
This is largely in keeping with the rest of the Iranian government, however. Apart from those involved directly in the negotiations, who are eager to take credit for the deal, there has been a sense that they should wait for the US Congress vote on the matter before they are too supportive.
While many officials are eager to be contrarian to the US position, they also don’t want to be loudly pro-deal and then see it blocked by the American Congress. No other parliament worldwide is expected to vote on the matter, and US officials say they believe the deal might go through more or less with or without the US as a partner.