Hmm.. you did quite well in kicking my ass on many of these points, primairly the US never having been truly isolationist, however there are some things I do question:
Um, though the US did get dragged against its will into Kosovo/Bosnia and the Israeli/Palestine issues, um, is it not a sign of weakness on the US's part for giving into such pressure to participate?
Then, the six major goals of the US foreign policy, though an near-isolationist policy would not meat these goals, um aside from the defense of home soil and protection of the environment, what exactly does the US have to gain from the others, and why should the US want interest in those. Also, I know the US has a major reliance on oil, but I'm much for abandoning all foreign oil and instead, enacting mass drilling on home soil to gain that same amount, as well as mass investment in alternative fuel sources that could effectively replace oil. Sounds a lot safer than dealing with the Persian gulf.
And, this is curiosity, not disagreeing with this point: what would of been the results if the US had not participated in either world war, or had had nothing to do with Bush the I's gulf war or Kosovo?
It is not a sign of weakness that they got dragged in. Rather, it would have been severely damaging both to the reputation of the United States and that of the United Nations if we hadn't gotten involved, because in the Kosovo and Bosnia cases at least, it demonstrates that we turn a blind eye to genocide. In the Israeli-Palestinian case, it would signal that we shirk away from our leadership duties as a superpower. And believe me, where the absence is, people notice. National prestige is way more important than you or even I can fully fathom.
Eurasian great power peace is very important. Because we've lived in an almost conflict-free Europe for the better part of a century, we've forgotten what it's like when states with significant regional power duke it out on the Continent. And that's not even limited to Europe; think about keeping the Russians at peace with Georgia, keeping Iran and Iraq from butting heads, keeping China from fucking everybody...that's what makes Eurasian great power peace important. If we don't rein it in, it's dangerous not only for us but everybody in the area, and eventually the crisis spreads across the international system.
The opening of international markets...I feel like that should be so obvious that I don't need to explain that. Riceball you can go ahead if you want to, but it's common sense to me so I don't really know how to explain why it requires we get involved in foreign affairs. The best I can do is to say that open global trade requires opening markets in different countries around the world, getting them to drop protectionist policies and things like that, convincing them of the benefits of immersing themselves in global trade.
To democratization: the democratic peace theory. There are other (far more significant) implications but I'm so exhausted, I don't feel like getting into it.
The Persian Gulf oil thing can be avoided by alternative energy development, and I am a strong proponent of clean tech (as should be obvious from all the rest of my P/R activity
), but that day has not yet come, so in the meantime, it's up to us to ensure that no one country becomes so great a regional power that it forms an oil monopoly. Not to mention this vital interest obligates us not only to our own oil security interests but to that of our allies; even if we make the alternative fuel switch, doesn't mean we won't be required to ensure oil security for an ally that hasn't.
If the US had not participated in World War II: the global financial system and international monetary system would not be based on the dollar, thereby preventing America from becoming the wealthiest country not only of the day but in the entirety of human history, and Taiwan and the Koreas would belong to Japan. In fact, Japan might have had the monetary standard tied to the Yen instead, and they'd be the wealthiest postwar country and the wealthiest in the history of human civilization. Germany would belong entirely to the Soviet Union and the rest of Europe would most likely be in economic shambles absent the Marshall Plan, which may have led, however unlikely, to the eventual takeover of all of Europe, even Britain, by the Soviet sphere of influence. Also we'd still be suffering from the Great Depression unless Japan decided to bail us out, which they might've considering in this universe we didn't drop the bomb on them.
If we didn't get involved in Kuwait: Iraq would have created for itself an oil monopoly in the Persian Gulf, well before anyone was concerned with alternative fuels, making our procurement of said oil extremely difficult. Our nation's pro-Israel leanings would have made the consequences of said oil control even worse, as Iraq would be able to twist our arm on any Middle East policies of ours he didn't approve of by manipulating oil prices or cutting us off entirely. Iraq would also have nukes by now, and instead of talking about the nuclear standoff in India and Pakistan we'd probably be talking about the one between Iraq and Iran. Oh and Israel would be a crater by the end of the (last) decade.
If we didn't get involved in Kosovo: the consequences of this one aren't as severe (for America, anyway), but they do hurt American prestige. As I said, the world was looking to the US to provide some leadership in the face of what was obviously genocide, having just gotten off the heels of another genocide just next door. There would have been accusations of American favoritism and things of that nature; our entire interventionist strategy would be completely discredited, and the UN would be a useless, meaningless institution (yeah I know people already say that, but it would literally be a non-entity if we hadn't stepped in). By the way that last bit would result in the collapse of the collective/cooperative security doctrine, and with the rise of terrorism, the end of the Westphalian state system. In other words, the international system collapses into anarchy in which international law does not exist and anyone can attack anyone and there's no one to complain to or seek reparations from.
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Edit: Another point that should clear things up:
Physical security, Eurasian great power peace, and Persian Gulf oil security all represent vital interests: those things whose acquisition are of incalculable benefit to the US's well-being, and whose loss would be severe if not catastrophic.
The spread of democracy, the opening of international markets, and environmental protection represent desirable interests: those interests whose realization would bring about great benefits for the US and in some cases the world, but whose non-realization have only mild or minimal consequences.