The options don't work, and carry costs. That's why I'd let Iran build nukes and not worry too much about it.
You're entitled to your opinion, so I'll just agree to disagree on this one. I believe that, if applied appropriately, there are a number of options that have worked throughout the 20th century to influence a nation's internal policies short of military intervention. UN sanctions get a bad rap, but they can be surprisingly effective if used creatively.
No it wasn't. Not compared to Iraq. In troop strength, Iran has a whopping 500,000 soldiers to the 400,000 Iraq had. There wasn't much to pick from between Iran and Iraq in military professionalism either. Iran had better morale, and would at least fight back. But really, few conventional armies are a concern for the US.
Bush entered the office from day one discussing with his advisers plans to invade Iraq. It was a daddy complex thing. One had tried to "kill my dad", the other one hadn't. Saying that Iraq was invaded mainly because it was an easy target is an argument that could be used to prove or disprove any other war that may have started. Why not North Korea/Libya/Zimbabwe/Myanmar/Syria/Somalia/some other even more Beyond the Axis of Evil impoverished outpost of tyranny?
That's the conventional wisdom which disregards history before the Gulf War.
Militarily, you are quite correct - both the Iraqi and Iranian armies could not fight a conventional war against American forces and win. I doubt any nation on Earth could, truthfully. Maybe China through attrition, but even that is doubtful.
There is where the similarities end, though. Iran had a democratic government in the 50s, ousted by the US-backed Shah. Why? Iran is
the major power in the Middle East. Control Iran, you control most of the region. Keep in mind that the other states surrounding Israel at the time were not exactly friendly to anything Western. The Shah was, and the Iranian government was weak and ripe for takeover. Fast forward to 1979. US influence in Iran has skyrocketed, American corporations are making a fair bit of money there, but the Shah's popularity is gone (if he ever had any, truthfully) and the Islamist movement is gaining backing with promises of an Islamic republic that ends American influence. Not very good for the US, but due to the situation with the Soviets actual intervention is now impossible. When the Shah was ousted, Iran was supposed to become a democracy. A very anti-US democracy mind you, but democracy nonetheless. That didn't happen. Instead, a small cadre of religious dictators took power. Thus ended any hope of Western influence in Iran. Doesn't mean anyone wanted to stop trying though, which is why the US provided support to the Iraqis in the Iran-Iraq war. It's also why Iran has remained hostile (and rightly) to the United States.
This, in turn, led to what we know as the Gulf War. Saddam believed (wrongly) that the limited support he received from the US was in essence authorization to turn Iraq into the regional superpower and topple Iran's status, and for that he needed deepwater ports. It seems he genuinely believed that Kuwait wouldn't raise problems in the US (and thus the UN). Oops. Suddenly the American puppet had gotten out of hand, a situation that was quickly (in military terms, anyway) handled.
And yet still the problem of Iran persisted. After the events of the previous few years, the collapse of the Soviet Union, and increasing tensions along with increasing surveillance in the Middle East, nobody was contemplating forceful regime changes, despite the fact that Iran was increasingly gaining in power, and expanding their trade relationship with China. China has a major thirst for oil which Iran has happily provided. The Iranians don't truthfully need the Chinese, but (especially now) it's becoming more apparent that the Chinese need Iranian oil. None of this is good news for the United States, but after 1979 it has become patently clear that direct US intervention into Iran is not going to work.
2001 - Al-Qaeda launches a major attack on US soil, which still baffles me because it was a huge miscalculation as far as mid-east geopolitics go. I do wonder if they (Al-Qaeda) expected military strikes instead of outright invasion. Regardless, NATO arrives in Afghanistan, beginning what will become a debacle of epic proportions, though it appears that the US DOD forgot to read the intelligence briefs on the region. Whatever the cause, the [relatively limited, as far as invasions go] deployment to Afghanistan has been trundling along since.
NATO is now sitting in Afghanistan, mere spitting distance from Iran, the one major power in the whole region, the one power with a major trade relationship with China, the one power that is really the only major threat to regional stability if they ever do anything more than sabre-rattling. There's a choice: try direct intervention in Iran, try it elsewhere and hope it influences Iran, or ignore the fact that China, a strategic enemy of NATO (though not really declared as such openly), is benefitting immensely from the region. Military intervention in Iran is out - there is at least one lesson learned already in Afghanistan, and it says that you might win a conventional war, but if you're faced with a population that hates you you have no hope of winning. But next to Iran is Iraq.
Iraq was and is a non-nation, truthfully. It's a country that was carved out of chunks of other countries through colonial efforts. It had no overarching religion, no common ethnicity, large autonomous regions that opposed centralized governance, and a great deal of internal strife with an immensely unpopular dictator, both home and abroad. And if we could toss the dictator there, what are the chances this could influence the very large pro-democracy-but-anti-US movement in neighboring Iran? At the very least, Chinese access to Iraq's oil is now dependent on NATO's goodwill (and to be clear, cutting off Chinese oil is not a Western strategic goal; controlling it is).
It was a VERY shortsighted policy decision, but the invasion of Iraq was predicated on strategic goals and not regime change in just Iraq, nor bringing democracy to the Iraqis, nor American access to Iraqi oil, nor WMDs. It was based on strategic regional goals which could not and still cannot be accomplished by a military invasion of Iran. It is a hard target because it has a hardened populace to overt US influence.
Iran doesn't need nukes to keep the US and its allies out. Developing them is a good way to open the door to inviting them in. Iran's best hope of preserving their autonomy would be to give their populace a broad voice and eliminate their human rights violations, while pursuing a transparent nuclear power program. Taking those measures would eliminate any appearance of legitimacy in Western military action. The current situation is simply more likely to provoke it - and this time Western powers won't attempt an invasion, they'll just hit with tactical and destructive strikes.
Letting the Iranians develop a nuclear weapons program won't increase regional stability, it will decrease it. Iran's best defense against Western military intervention is not military development, it's social development.