Let me start off with saying, I am writing this without carrying out any research…no figures, no numbers and no dates. Just my impression on how successful they were in several of the "Wars" they have been involved in. A few that they have been involved is – Korea, Vietnam, star wars, drugs, illegal aliens and of course terror.
Verdict on each of them – resounding failure.
In Korea, US managed to keep the South and North isolated and it did not make much of a headway in getting the Kims to toe-the-line. North Koreans live disastrous lives and have managed very little beside pick up a nuclear capability from China and Pakistan. Now the South Koreans live in the shadow of this weapon and the world gets routinely blackmailed into providing food and medicines to the North. Not exactly my idea of a victorious end.
Vietnam was unnecessary, unending and unresolved. Today Vietnam is one country, and its capitalist outlook has as much to do with the success of the neighbourhood and the failure of Communism than a tribute to the US soldiers who laid down their lives for nothing. That Vietnam is now a large exporter to the US shows their maturity in managing their affairs.
Star Wars over nuclear weapon armaments in the US and the erstwhile USSR led to amassing of large numbers of weapons by both nations. Numbers are still debated but undoubtedly each country could end the world as we know, single handedly with a handful of them. Why they needed more probably has to do more with supporting the companies that were being paid by the exchequer than a real strategic need. All this brought about the Cuban crisis and major headache of keeping tabs of the warheads after the USSR dismantled. Hollywood probably thanks Reagan for given them this opportunity to presenting rogue nuclear sales in a hundred different ways. But then, that's not such a great thing either.
The drug wars are not yet over. Cartels from Central and South America source from Afghanistan via several known routes, process, package and smuggle them into the US with as much impunity as ever. Sure every few years you hear of a cartel being broken and heads rolling. But the menace is not gone. It has just gotten worse. There are new drugs being created, manufactured and distributed. The cash generated from these sales are possibly fuelling the global terror and more than one country is said to be in the clutches of these drug lords.
Watch any comedy show emanating from the US and the jokes about illegal aliens and more specifically of Mexicans is standard fodder. US has built miles and miles of fences, illuminated the borders, set up check points, tried everything on earth and yet they cannot stop Mexicans from entering their country by road or Cubans by boats. It has reached a state where people are questioning America's ability to survive as an economy if these aliens were not doing the menial jobs in the country. While one could debate how serious US is about stopping their entry, the fact is that a long shared border cannot be secured completely. This seems to be lost on all the Indians today baying for a secure border with Pakistan. If Mexico or Canada had been exporting terrorists, US could not have done much either. The 9/11 perpetrators came from thousands of miles, entered, settled, plotted and executed their plan with precision. They could not manage to stop that either.
The best is of course their "war on terror". Their partner in the war; the very country that fostered the terror. It took them close to six years to acknowledge there is no way to avoid acknowledging and two more to probably take more severe action. For sixty years they supported the various unelected governments in Pakistan unconditionally and did little to support the elected ones in the same way. They watched as guns and funds for the "afghan war" were diverted by Pakistan to its creation, Taliban and did little to stop Taliban from taking over Afghanistan when the Soviets left in defeat. Today with an ill designed plan on destroying terror in Afghanistan it is now letting Taliban take over parts of Pakistan. It is no where close to ending this war with its inability to find any of the following: WMD, al-Qaeda leaders, terror training camps, financing routes, anything that can actually be ended without finding new hydra heads emerging.
As for their role in the middle east goes, the lesser said the better. They have not managed to get Israel to agree to a true peace treaty that will allow Palestine to restart its life. They did not manage to 'get Saddam Hussein" for over a decade even after he tried capturing Kuwait and only caused major disaster for the Iraqi people through Sanctions. Their influence over Iran, Syria et al is less than mine over Indian foreign policy.
All they achieved through all these wars was a large fiscal deficit, an unmonitored economy, demise of manufacturing in the US and the current financial meltdown. A good lesson to learn for the rest of the world.