First President Obama inherited a disaster from Bush with ISIS as the largest military force in Iraq, and apparently you do not read up on what followed:
From:
Obama Announces Strategy to Destroy ISIS
President Barack Obama wants the approval of Congress as he announces a broad new air war against ISIS, including strikes in Syria, but says he already has the authority he needs.üüIn a speech outlining a new strategy to destroy the group also known as ISIL or the Islamic State, Obama announced an extensive air campaign with no set end date, and plans to rely on others to engage in a ground war — Iraqi forces in Iraq, and Syrian moderates in Syria.üü“I have made it clear that we will hunt down terrorists who threaten our country, wherever they are. That means I will not hesitate to take action against ISIL in Syria, as well as Iraq. This is a core principle of my presidency: if you threaten America, you will find no safe haven,” Obama said.
. . . and he launched an intensive covert campaign to capture and/or kill Osama, which was successful.