Being more aggressive with ISIS over the last 5 years could have had a wide range of results. At the two extremes:
(1). ISIS is crippled. Without centralized planing and support, the jihadist movement is crippled and terrorism quiets down worldwide. Russia and the US reach an accord over how to handle the Middle East, and the prospect of long-term peace becomes real.
(2). The attacks on ISIS result in large numbers of innocents to die. Outraged, thousands of previously nonviolent Muslims become jihadists. Local terrorism mushrooms out of control. Russia and the US can't agree on how to handle ISIS of other issues in the Middle East, and we find ourselves on the brink of WWIII.
So, maybe Obama the Fool has blood on his hands, or maybe Obama the Wise has saved countless thousands of lives. Anyone who subscribes firmly to either of these possibilities is, imho, speaking from the wrong orifice.