"I dont think US will take any action unilaterally..."
The U.S. will do what's necessary to assure its interests and those of its regional friends. Our interests aren't met by an Iranian nuke.
As to means, neither our airforce nor navy are
overstretched by any definition.
Should we decide to take down the Iranian capability, it will be done via a sustained air campaign lasting however long is necessary to get Iran to submit to full dismantlement of their present capabilities and indefinite monitoring until satisfied with a posture of cooperation and compliance.
Most here haven't followed closely the path this has gone since 2003, are ill-informed on the particulars, and know nothing about our capabilities and determination to exert our will. The Iranian government isn't going to be allowed to establish itself as a regional nuclear-capable hegemon over the gulf.
We will kick down their IADS (integrated air-defense system), open ingress and egress air corridors over Iranian airspace, keep those corridors open as long as necessary and bring our heavy dump-trucks at will.
We will destroy the Iranian Air Force, its naval facilities, the IRGC-related facilities while likely preserving the Iranian army. We will bomb every known or suspected nuclear-related facility until they're gone. If necessary, we'll take out the nat'l communications and electrical grids.
Our troops world-wide will go to a very high state of anti-terror alert. So too our embassies and other related national facilities. We will, in short, do our best to limit Iran's ability to react assymetrically.
We will preserve to the best of our ability Iran's oil producing apparatus. We will, to the best of our ability, attempt to avoid civilian casualties.
Most of all, we won't give a good God damn what AhsanR thinks to achieve such. Iran has built its current duplicitous ambitions on the back of assistance provided for years by the IAEA because they are signatories to the NPT. Surreptiously pursuing a nuke IS NOT part of that agenda and doing so means that they're slimey worms who's word IS NOT THEIR bond to the rest of mankind. We won't permit them to single-handedly destroy that non-proliferation regime that's had too much success providing safe nuclear energy to the world.
Iran has been offered inducements beyond reason. They will face sanctions beyond belief. If that doesn't work and there's a clear and present danger, all hell shall rain upon their heads and there's NOTHING Russia nor China will do about it.
Thanks.