Consider this a thought experiment.
If Country A wants war with Country B, but also wants to be the righteous party, and suffer the least possible consequences to itself and its allies, how does it go about this?
First, Country B would need to be Isolated. They it will need to be "defanged" in order to control any possible damage to itself. Then the best part - Country B needs to be made desparate enough to be forced to attack first.
No innocent country attacks first. The Defender have the moral highground on their side.
Now let's apply this. Replace "Country A" with "USA" and Country B with Iran.
An overly simplistic analysis of Iran is (rather, was) that it has its own conventional forces, but it also has contacts with the outside world through its export of oil and its alliance with Syria and Hezbollah, which may retaliate "on its behalf".
In other words, the silent threat was "attack us and Hezbollah will attack Israel".
Isolation here is through a two pronged process.
Step 2 is to remove the teeth of Iran's regional attack dogs. These being Hezbollah and Syria. There have been attempts by another actor (either unilaterally ot through covert and overt support) to defang the first of these, Hezbollah. These have been unsuccessful.
As for the second, the Arab spring brought great fortune here as it with a little help has paralysed Syria and Syria is less likely to defend its ally Iran. A great strategist will always use the great fortune to its favour and here too, while the movement for freedom is organic and natural, other powers-that-be will naturally jockey to take advantage of any great advantage that they are thrown.
The Assad regime ofcourse didn't help - it had a chance to avoid all the chaos and bloodshed - before the regume went into overdrive, Assad was the most popular ruler, real or potential, in Syria. Any concession would have meant he kept all his power and initially the regime kept its support. This changed when elements within the regime decided to attack some kids in retaliation for their grafiti - the greatest own goal in history. From here things have escalated.
So this limits the support from Syria, and as Syria helps Hezbollah, it also potentially limits the help from Hezbollah (notice recent Israeli air strikes destroying alleged transfer of weaponry from Syria to Hezbollah).
Now that Ive mentioned step 2, I can logically move on to step 1.
Isolation. This has been by weakening the logistical allies of Iran. But it has been much more. Sanctions. The favoured weapon of the western regimes.
The idea is to tighten the screws so tight that others are unable to help Iran without seeming to be allied with it. This has the added benefit that it also builds desparation.
A slight digression here: Iraq. In 1990 Iraq a huge oil country was in dire financial straits and its fellow countries were not helping. Iraq had just been in a long war with Iran with huge financial penalties.
At this stage unhelpfully the price of oil, the lifeline for the country, tanked to such an extent that pension payments to the huge numbers of war widows had to be cut.
And then there was Kuwait. There was a disputed oil field between the two countries. Kuwait decided that it was in its interest to exploit the oil in this disputed oil field and not only that, but to deply something called "slant drilling" in order to get the oil that was under Iraqi Territory.
The screws were tightened and Iraq was made desparate enough to invade Kuwait. Then it was destroyed.
(Having a maniac as its leader did not help Iraq. The west knew its many crimes as they had often helped in carrying them out or provided infrastructure or materials that let it happen. Its the same way they knew it had chemical weapons - they were the ones to sell it in the first place!)
Now back to Iran. It needs to be made not only as despparate as Iraq, but moreso - it knows what happened in Iraq, and its best to ignore the media image of Iran as being run by lunatics, there will be some sound minds in there too aware of what happened before.
So first there were sanctions. they were "targetted" and "intelligent" sanctions. You will often hear the same words to describe western missiles and other explosive devices. These words are often there to mask their indiscriminate nature.
But these were not enough and initially they were aimed at the nuclear development that was potentially taking place in Iran.
Then these sanctions were tightened. Then more were added. All in the name of preventing Iran from developing nuclear weaponry.
Red lines were also added - if Iran got close enough to being able to build nuclear weapons, it would be stopped.
Another digression - there is another country, that has nuclear weapons and is desparate to be given the credit for them - North Korea. It has just spent a month threatening the US and its allies with war, but for some reason it was not seen in the same light as Iran.
Back to Iran. The excuse of Nuclear weapons being the reason for the sanctions was exposed a few years ago when Turkey, Brazil and other countries came to an agreement with Iran that would have prevented it from building nuclear weapons while still being able to exploit nuclear power.
The response of the US? It was Furious. How dare these countries actually negotiate a peaceful solution with Iran!
Sanctions were imposed through the UN, which were draconian, but this was not draconian enough for the US.
So it imposed its own - preventing Iran from using the global currency of the time - the US dollar, and if any company, country or financial institution wants to deal in/with the US, it must abandon Iran.
It allowed a few countries to continue trading as long as the amount of trade was constantly being reduced and ended by summer 2013.
That is where are now.
Iran's allies are being defanged or controlled so that their output is controlled. Iran is being isolated and prevented from trading with the world and naturally this has the added benefit of building desparation.
Iranian passenger aircraft have trouble fueling abroad, as if they are refueled by any company, that company can then not trade with the US or it companies.
Iran is unable to buy machinery or replacement parts of highly technical vehicles (once again using aviation as an example, replacement parts passenger aircraft are dificult to impossible to obtain).
Countries buying Iranian oil are being forced to stop buying and trading in it.
Iran is being prevented from exporting its excess productions (mostly oil) and importing any other goods it needs (mostly everything else).
This is all building desparation and when desparate people lash out. So do countries.
If Iran does, it will be presented in the media as proof of the madness of the mad mullahs, and not of a carefully orchestrated plan that bgrought Iran to its knees for precisely this reason.