The Concert of Europe required Metternich and Tallyrand to put it together. I don't know if such people exist any more. The Concert of Europe did provide a period of generalized peace as you note. The Crimean and Franco-Prussian Wars were the only breaks in the order. The Concert of Europe also ushered in the period of Pax Britannica. I wonder if Pax Britannica had anything to do with the maintenance of the era of generalized peace between the great powers.The period to which I'm referring is the roughly 100-year period often termed the "Concert of Europe." During that time, there was only one fairly significant war in Crimea. Unpopular as it might be, I would suggest that the outcome for that period was quite superior to the period that began with the establishment of the UN. Since that time, there has been two to four fairly significant wars (Korean War, Vietnam War, Persian Gulf War, and Iraq War) and numerous smaller wars, including some very bloody civil wars in parts of Africa, the Balkans (twice), Middle East, etc. My guess is that careful management of the balance of power (where sovereign states focus on their interests) is a better approach to stability than world organization (where states with vastly different interests are expected to ignore those interests to find the common ground necessary to preserve stability).
Some historians maintain that an era of generalized peace requires a hegemon rather than a balance of power. The hegemon will of course fight peripheral and limited wars, but other great powers are deterred from directly challenging the hegemon through total war.
If the Chinese Communist Party is to maintain power the Chinese economy must continue to grow and lift significant numbers of Chinese out of poverty. Toward this end, China must control the sea lanes from East Africa to the Yellow Sea. That will bring Chinese interests and Indian interests into conflict. Their rivalry will be the great contest of the first half of this century imo. If China controls those sea lanes India's rise will be aborted. India cannot allow this if it is to become a great power.China's rise is not without barriers. China has a rapidly aging population (far larger issue than the U.S.). China's political structure faces challenges presented by the country's continuing evolution (the recent internal turmoil highlighted by the removal of Bo Xilai offers a symptom of that larger challenge).
I agree. Yet I would take things a step further. The greatest factor in international relations for the foreseeable future will be ethno-nationalism, not internationalism. If I am correct in this belief western style internationalism is going to take a back seat in the new era.Finally, a focus on the national interest is not necessarily a bad thing. It can facilitate prioritization. It can avoid the overreach and consequences of overreach that are an inherent risk of a pursuit of ideals beyond the constraints of the national interest.
America can engage in the balance of power in a multi-polar world...even as first among equals. But to do so it must husband its strength and resources. This requires avoiding armed conflict with other great powers which would dissipate that strength and those resources.