Gen. John R. Allen, USMC (Ret.), has a column taking a contrary view:http://www.defenseone.com/ideas/2014.../?oref=d-river

He does write that the USA should not act alone:
The whole questionable debate on American war weariness aside, the U.S. military is not war weary and is fully capable of attacking and reducing IS throughout the depth of its holdings, and we should do it now, but supported substantially by our traditional allies and partners, especially by those in the region who have the most to give – and the most to lose – if the Islamic State’s march continues.
To date I have seen very little regional support - excluding basing. A number of nations, families and individuals have financially supported the Jihadists - little sign of that stance changing. No mention of Iran either, hardly a 'traditional' ally (see main Iraq thread and Crowbat's recent explanation of their role).