US in Iraq

Since the US takeover of Iraq from the brutal regime of Saddam Hussein, the Iraqis were more suffering than ever. The Iraqis thought that they have been freed by the US (skeptically) from Saddam's repressive administration, however, the situation got much worse.
The US claim of the US attack Iraq was initially the link of Saddam with al-Qaeda, which was proven wrong. Afterwards, that Iraq has Weapons of Mass Destruction; again, it was a fabrication. Later, that it wants to establish democracy - by force?
Now, after 4 years the Iraqis are in shambles with all the bombings and killings everyday of their lives, and they want the US to pull out its (and its allies') troops from Iraq - but the US insists that Civil War will start when the troops pull out.
This is unbelievable. Security in Iraq at present is in its worst condition than ever. The US presence in Iraq has no capability to ease the situation but it makes it uncontrollable. And ever since, the Sunnis and the Shiites have been coexisting peacefully and harmoniously. . So the claim of the US of civil war upon their pullout is baseless.
Besides, it is a shame for the US, a 'superpower' at that, that it cannot contain the violence happening in Iraq, and it gets worse everyday right before their very eyes.
Actually, this is what they call the "good cop-bad cop approach". The US has an agent (al-Qaeda) to destabilize Iraq, and the US military will declare their stay in Iraq for security. What security? For whom?
The US cannot really do a damn thing. They should pull out of Iraq to save their soldiers' lives, and Iraqis too. Not to mention huge financial burdens for all concerned