War, which by its nature is horrific can indeed be used to achieve a "victory". If by "victory" we refer to a positive outcome, then one need look no further than the 2nd world war, the threat that Nazi Germany posed to the rest of the world naturally called for military action to be taken after all diplomatic negotiations failed (Neville Chamberlain). In fact if Chamberlain had not followed his policy of appeasement and instead decided earlier on that Hitler was a threat, when the Germans military was weaker, then the combined French - British forces may have been able to crush the Nazi forces before Hitler the "final solution" began. If Chamberlain had of intervened sooner in the war instead of waiting 7 months in the hopes that Hitler would negotiate, then Nazi Germany would not have been able to regain it's strength and would not have invaded France, Norway etc. WW2 shows that diplomacy is not always the best solution, particularly when the threat is great. Military action is required at times, particularly when the enemy is militaristic and imperalistic in their ambitions, ultimately if we where to do a cost benefits analysis of whether we (the allies) should have fought Nazi Germany, then the cost of war is less than the cost of allowing Nazi Germany to pursue it's (in my opinion evil) ambitions. (Note: I'm not a neoconservative, I also retain respect for diplomacy, but also believe that war can be a necessity that can wield a positive outcome or "victory").
War does not solve problems it creates problems. If you look back a war the United States has won like WW2, It has created much more issues than good. Israel is a mess and Americans have created stereotypes and racism to specific countries like France and Germany. Also, many people die as a outcome of war. There are usually no deaths in a diplomatic resolve.
While ugly, war is necessary to protect the innocent against an agressor state or non-state actor such as terrorists. In that sense, if a country loses land or gives us, it is defeated in war, and therefore there is a winner, even though both sides suffer tremendous losses. War should always be avoided, however.