Char;es Krauthammer has ISIS's game plan all figured out:
... What was the Islamic State thinking? We know it is sophisticated in its use of modern media. But what was the logic of propagating to the world videos of its beheadings of two Americans (and subsequently a Briton) -- sure to inflame public opinion?"The quintessential such leader"! So ISIS has calculated that Obama is a big wuss -- but not quite enough of a big wuss to shrink from the fight altogether if provoked, just enough to start the fight, get embroiled in it, then quit, just the way he's done in, oh, say, the fight against Al Qaeda, in which ... um ... he's killed the leader and some top subordinates, thus helping to create precisely the competition for the title of Earth's Baddest Jihadist Group that ISIS is currently trying to win.
... It was an easily sprung trap to provoke America into entering the Mesopotamian war.
Because they're sure we will lose....
They count on Barack Obama quitting the Iraq/Syria campaign just as he quit Iraq and Libya in 2011 and is in the process of leaving Afghanistan now. And this goes beyond Obama. They see a post-9/11 pattern: America experiences shock and outrage and demands action. Then, seeing no quick resolution, it tires and seeks out leaders who will order the retreat. In Obama, they found the quintessential such leader....
Oh, and Obama is so uniquely and predictably feckless that ISIS can count on him not to give in to pressure to widen the war, and to cut and run before another U.S. president (maybe even a Republican!) can fight ISIS more effectively (because who could possibly fight ISIS less effectively?). It just isn't possible, according to ISIS, that Obama will hold the line, or even score some victories, then hand the war off to an able successor, even though he'll be president for only two more years. ISIS is counting on Obama to pursue the fight to exactly the extent that maximizes ISIS's glory, and then to withdraw exactly when the fight can't be rapidly escalated by whoever succeeds him, all because Obama is such a uniquely terrible American leader.
Why, it almost seems as if ISIS thinks exactly the way Charles Krauthammer and his Fox News buddies think. Odd how that works.