Is the Crisis in Iraq all America's Fault?

Afghanistan's President Hamid Karzai has said that he believes 'Iraq was a stable country before the Americans went in there". He added that 'the war on terror was not fought with honesty and not fought genuinely'. Eleven years on from the US-led invasion that ended Saddam Hussein's rule in Iraq, the country is in the middle of another serious crisis that is threatening long term security in the country. In the latest fighting, the Iraqi army says it has driven off Islamist-led militants attacking the country's biggest oil refinery amid reports that it had been overrun. Is America ultimately to blame for what's happening in Iraq? Who is responsible for the emergence of ISIS and Iraq's instability?