AR1 makes a good point. Typical CVN deployments are 6-7 months, with the occasional extensions beyond that when heavy ops crop up. Op Tempo and all that. We got extended in Sixth Fleet a couple of months back in 86...the "six month deployment" ended up being a few days short of eight months when all was said and done. Ford was due to come home. (If nothing else, to fix the heads.
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As to this thought:
Why is it so important that they don't have one?
Best to ask that question of the Israelis.
But also ask, within the region, the Saudis. As we've discussed before on the Mil Av forum, there is a valid concern that if the Iranians reach their goal, the Saudis will have one rather soon...balance of power stuff, if nothing else, and I harbor a suspicion that Pakistan will be who provides it to them.
My opinion on the Iranian nuclear capability remains what it's always been: they'll find a way to get it, and then they get to add themselves to the list of places on our (the US) target list.
Be careful of what you wish for.