5000 officially from US sources, but more than 50 000 from Iraqi count of US casualties, a realistic number if one is to believe that 1000 000 Iraqis lost their lives in the conflict, that was easy in Iraq though, since it is all flat terrain and Americans went on a hunting party...
This is age of information and deception. Can you validate 50,000 KIA figure? In older times, it was easy to conceal facts. But situation has changed in the 21st century. In fact, US is very open about revealing its casualty figure in warfare; more so then many other nations.
Terrain wise, Iraq is not a paradise either. Much of the country is filled with desert and northern regions are mountainous. Desert conditions pack challenges of their own.
Iran is too mountainous for a land invasion and too fierce in a fight, Hezbollah war in Lebanon of 2006 is but a tiny sample of what awaits America and Israel in particular and the whole region in general (relatively speaking, since it might spread very quickly to a WW3 scenario if China - which never jokes in these matters- enters the war overtly to protect Iran and itself eventually).
Do not confuse IDF with US armed forces in terms of warfare capabilities. According to Iraqi commanders; IDF pales in comparison to US armed forces.
Also, US have learned a lot from Afghanistan about fighting in mountainous regions. And if you expect me to believe that entire populace of Iran is Rambo-like; don't.
Also, do not kid yourself with the assumption that China will aid Iran. This is not COLD WAR era during which China used to be much more economically independent.
The USsrael never dared to speak about invading Iran (just an air campaign to destroy the Iranian nuclear installations, but the latest remarks from the highest military officials of the US are telling Israel to keep its sickness to itself and to be realistic. Iran is extremely powerful militarily speaking.)
Present geopolitical climate does not favours another Iraq style invasion. Iraqi mission was not positive for US image. But reasons for not attacking Iran are different from what you believe. Iranian military might and political outbursts do not scare US. You should remember that US was/is willing to thwart any Iranian attempt to block Straight of Hormuz as an example.
In case of Israel; Iran is in beneficial position of not being located geographically close to Israel. Any attack from IDF will be very ambitious mission and may be carried out after reaching non-interference agreements with neighbouring countries in the path towards Iran.
Here is a sample of what was happening in Iraq day in day out when the Iraqis decided to fight the Americans, at the rate you will see in the following video, 5000 US casualties can happen in few months, imagine 8 to 9 years... that is why the US leaved Iraq... in panic mode.
War is messy business. But you cannot generalize about the whole picture on the basis of videos like these. At the end of the day, US army wasn't wiped out in Iraq or was it?
Iraqi resistance movement began in 2004 and peaked during 2007. However, it lost its momentum and effectiveness afterwards when US took the challenge very seriously. The situation became so dire for Iraqi clerics leading resistance forces that they had to flee to neighbouring countries. Most prominent example is of
Muqtada Al-Sadr.
Check this link for momentum of insurgency related activities in Iraq:
Interactive: A timeline of violence - Secret Iraq Files - Al Jazeera English
For detailed analysis;
Varieties of Counterinsurgency: A Case Study of Iraq, 2003-2009 (Jon Lindsay) - Academia.edu
And US withdrawal process from Iraq is among the most peaceful events in the history of warfare; let alone in modern times. So what kind of panic mode you are talking about?
US left Iraq after stabilizing it, preventing its breakup, implementing democracy and developing modern Iraqi armed forces. Get your facts straight.
This is ONE sniper who made something like 1000 American casualties in one year in Baghdad, the same thing was going on in every Iraqi city with thousands of snipers all over Iraq.
The US could lose all its soldiers in Iraq very quickly if it didn't hide them in their barracks and had no other choice but to leave this Muslim Arab place called IRAQ.
Baghdad sniper kills Americans mice - YouTube
Sorry brother; the 1000 figure seems like a fictional account.
Check this realistic account:
Amazon.com: American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History (9780062082350): Chris Kyle, Scott McEwen, Jim DeFelice: Books
Also, US military performed really well in urban environments of Iraq. As an example; here is Chinese assessment of the most iconic US military engagement against forces of resistance in Iraqi history:
http://sa.rochester.edu/jur/issues/fall2007/chang.pdf
It is apparent from your posts that you are in absolute denial about the ground realities of war in Iraq. Sorry.