.. if the danger ISIS presents to the sovereignty and people of the United States satisfies a threshold to justify war, then we should not tarry in attacking Russia, China, North Korea, Pakistan, Iran, Cuba, the Mexican drug cartels, or otherwise.
Moreover, even if we destroyed ISIS, the dynamics behind its creation would remain to create a new variety, just as ISIS has eclipsed Al Qaeda:
namely, utterly dysfunctional and tyrannical Arab governments ruling over artificial nations whose boundaries were drawn by a handful of donnish European diplomats a century ago with ulterior motives.