Hillary Clinton's time as Secretary of State was to take out dictators like Quadaffi and Mubarack without thinking about who would take their place. In Libya, you get Muslim militias instituting the harshest religious law, and help for Boko Haram to enforce Shariah law in northern Nigeria. In Egypt, the Muslim Brotherhood was big enough to organize as a political party, get voted in, and start implementing Shariah law before a military coup kicked them out.
Hillary did the same in Yemen, which is still in civil war so bad the Saudis have built a wall around the country to contain it. And she tried to overthrow several other dictators, assuming that the bad acts they did were out of spite or power lust, not realizing these mostly secular dictators were controlling even worse people.
Hillary was incompetent/ignorant to think that Russia would let her take out Assad, a dictator that let them have a large military base on the Mediterranean. Russia stepped in to defend the local leader who let them use a major military installation for free, leading to a bloody four year war - her fault, because we had no fighting in Syria or fighting with Russia. She looks at Russia as if it is the 1980s, the Cold War, while failing to see they are our natural allies against Muslim terrorism. They've been fighting in Chechnya and regular terrorist attacks for years - and we can use their help. Their Arabic translators, for example, are usually secular, not religious and prone to sympathy to fundamentalists.
But Hillary Clinton didn't even pay attention to the militias she armed in Syria to fight Assad were using the same weapons to fight us in Iraq to create the ISIS state. ISIS, and all its atrocities, only exists because she armed them under the foolish belief that the enemy of our enemy is our friend.
The proxy war we're having with Russia in Syria and the entire Middle East in flames is HER FAULT.