He said action will include military, diplomatic and economic components. Really? Diplomacy does not work with Islamic extremists as they can't be trusted; ask Israel. What economically does he think he can do to them? Somebody is providing some serious financial assistance to ISIS. How else could they accumulate $2B?
One country I strongly suspect as providing ISIS with financial support is Qatar. They want to construct a gas pipeline from their country all the way to the coast of Syria to reduce their costs of shipping natural gas to Europe. They can't construct the pipeline in Syria with Assad still in power as he opposes it. Saudi Arabia also wants to construct a pipeline to Syria's coast to reduce their costs to ship oil to Europe. They can't with Assad in power.