The problem in Iraq has a direct correlation to Syria in that as much as Saddam Hussein was a peril in the country, ousting him has left this space for the ISIS rebels to fill.
As much as Saddam was no good he ruled with absolute power so none of the jihadists were able to use Iraq for the means that they are now. When we invaded/assisted in 2003 we removed the power from the state and as much as we tried to reinstate a democracy, the country has to be reliant on all sides within the country seizing the moment and creating a government that is able to withstand such forces.
Unfortunately this hasn't happened hence the rather simple take over which is taking place at the moment.
We can't go back in but feel compelled because we have already been there and acted as some kind of catalyst for the situation now.
And as GGG says Assad being voted back in is a sense of mis-achievement for the whole country but with an over ruling majority wanting Assad in power it's much like the struggle in this country in that people may have made the decision to vote based on the fact that there is nobody better to vote for.
It's a sorry state of affairs on the news at the moment with the Boko Haram and the shootings in America/Canada, Syria, Iraq and the Russia/Ukraine conflict.
I for one am glad I don't have to make the decisions that may dictate the lives of thousands.