The US has to have limits on the use of its power in line
with the threats to its core interests. It has always been so and will continue
so. To call the Vietnam and the Iraq wars waged by the US and others to be
outside the US limits of use of power is a furphy that conveniently shifts the
blame of losing these wars to the argument that they shouldn’t have been
started in the first place.
The reality is the US just physically cannot police the world and keep it safe for the majority of the peaceful nations in the world. Obama has acknowledged this and has revised where he feels the US core interests lie in his speech at West Point.
The reason why these wars have been lost is the absolute refusal of the free world to take responsibility for its security with funding, equipment and military personnel in line with their GDPs to support the US in its quest for world peace.
Iraq is an example where the US left a nation with every chance of going forward with democratically elected governments and due to outside influences and a lack of hunger for freedom this outcome seems an impossible dream.
The US is going to try to stem the tide in a limited way but the solution would be if more than 200,000 Western troops and equipment poured in and reset the status quo in order to enact a political solution. Even if the US supplied 50% of this force and the coalition the rest the US would be doing more than its fair share of heavy lifting.
Failing this the West will just have to get used to an increasingly dangerous world where bombings and terror become the order of the day.