It seems like nobody remembers the fall of the Soviet Union. 

Iran is a country of 90 million people with remarkably unfriendly terrain. 

Their regular military is around 900,000. 

They have around another 3-4 million armed Islamic radical types. 

They haven't been "decimated" at all. Sure, we've destroyed infrastructure and killed some leadership and threatened the energy balance of the entire planet. But, decimated? Not even. 

It's said that Trump wants to send Troops to Kharg Island. Look where it is and tell me how that's going to work out? 

We couldn't "win" in Korea. We couldn't win in the jungles of Vietnam. We didn't win in Iraq, really, and we certainly didn't win in Afghanistan. And none of those countries were even remotely like Iran. 

In two months you'll start seeing severe energy shocks in Europe and parts of Asia, probably. Maybe allies like Australia and New Zealand. Hell, it may already be too late.