Islamic radicalism has been around for a long time (the genesis of the Muslim Brotherhoods can be traced to the 1920's), so ISIS or whatever name they morph into will be around for a long time to come, unless and until there is an effective counter message which is more appealing to the population than radical Islam.
Like European Christianity, Islam is also split into violently opposed factions; in Europe this climaxed in the 30 years war (ending in 1648), and I expect the Shia and Sunnis are teetering over the edge of a similar religious conflict, probably with similar horrific results.
Right now, *we* should NOT be expending Western blood and treasure fighting ISIS; the Iranians are already fighting them with their Quds forces, SU-25 ground attack aircraft and Hezbollah fighters (bought and paid for by Iran), let them take the risks and absorb the casualties. All *we* need to do is park a few carrier battle groups off the coasts to keep the fighting contained and put on popcorn.
To support our own foreign policy objectives in the area, *we* should continue to support Israel, Jordan, the Kurds and Baloch people so *we* have an in later on, but otherwise leave them to their own devices.
