Sanction is not an effective tool for resolving international conflicts.

Sure they are. At least over the longer term. I can give you many examples: #1 - Napoleon and his Continental System - unable to invade England, Napoleon went with economic warfare. England however did not stay silent on the matter, and actively blockaded European ports, preventing them from garnering commerce from their far flung colonies. At some point, one or the other was going to induce enough pain that one side would break. That side was France, when Russia broke away, desiring trade. That forced Napoleon to invade Russia to restore the economic warfare, and obliterated France's military potential. England's 'sanction' prevention of trade with colonial supplies, even as Britain garnered those resources from its colonies, broke the stalemate and lead to the end of Napoleon. Sanctions worked, and had a discernible effect on both sides when employed in conflict. #2 - WWI - Sanctions were a major consideration in the resolution of WWI. The blockade of Germany reduced Germany to near starvation levels, and, as the war was attritional, arguably had a massive effect on the ability of Imperial Germany to sustain its war effort. #3 - the Cold War. This was resolved precisely because of sanctions. The two blocks did not trade, and the economic engines were thus stressed to sustain the empire. With Russia holding down Eastern Europe, pushing into Afghanistan proved too much and the economic ability to sustain its empire crushed under the weight required to support it. Russia was defeated. The alternate solution? The invasion of Russia was never really a viable option. Sanctions produced the same end result that a MUCH more expensive invasion would have produced. Containment (Sanctions) worked. #4 - Burma. Long term sanctions eventually brought about massive political change, with the military junta releasing Aung San Suu Kyi. The state has itself noted the effectiveness of sanctions and are using them against their Rohinga minority. Like any tool, they can be used for good an bad measure. #5 - Iran. Its not military force that has brought Iran to the negotiating table in seriousness, its economic sanction that has hobbled their economy. They sought and continue to seek, relief from crippling economic sanctions. They are working. #6 - Russia. Russia could just grab Eastern Ukraine. The threat of sanctions alone has had implications for Russia, involving Capitol flight, higher borrowing costs, and economic contraction. The threat of genuine sanctions targeting larger aspects of the Russian economy have caused them to reconsider the costs, and they are now ... if not helping, at least no longer actively undermining the process. It may still fly out of control, but we no longer have Russia deliberately fanning the flames precisely because their economic leverage has been threatened. #7 - China is using sanctions very effectively. Its blocking of rare earth mineral exports (as sanction) was a shot across the bow. They routinely manipulate trade issues to force concessions out of the neighbors. They are usually more successful than not. #8 - The use of National policy is generally thought through the DIME analogy, Diplomatic, Information/Intelligence, Military, and Economic. The last portion there is aimed directly at harnessing the power of economic might and advantage. It is a powerful tool against many of our enemies, we can freeze them out of International Finance, block the movement of money and fund raising, etc. That makes things MUCH harder for our adversaries and its why we use it. When we combine it with intelligence? When we force the movement of money into restricted paths, we can follow it - and we do. That allows us to then use diplomatic (heh, put that dude in jail) or military (Al Qaeda meet drone) to eliminate the issue. Sanctions are often effective over longer periods. They hobble our adversaries, which is one of the main reasons, for example, that North Korea is not nearly as aggressive today as it was when it was unbridled with financial and military resources flowing in from Russia. It is now dependant upon China, and China uses that economic influence with North Korea routinely. North Korea is bellicose, but its a far cry from the 1970's brush war that swept the DMZ. Simply put sanctions work. And they often work very well when they are combined with the other instruments of state power. Its not a panacea though, sanctions, particularly without enforcement, are not effective. But there are obvious cases that properly enforced sanctions have produced results and done so with far greater results than other options. DO you think invading Iran would have brought them to the negotiating table? Or would we have another Iraq on our hands? A bloody mess spinning out of control? Simply put, sanction work - especially when part of an overall state effort in which economic pressure is brought to bear and coupled with a reasonable way out of the resulting economic drought.