Yeah, but do you really think it'd be a unipolar world? Don't you think other countries would react badly to America basically holding a gun to the world's head whenever it wanted something? This'll be very different from the Cold War, because in the Cold War we were only going to attack the Soviets and the WP (and some others depending on the year). In this timeline, the only logical thing to do is to ostracise the US unless they share the technology. That or the rest of the world has effectively become an American colony.
Actually scratch that, the only logical thing to do would be to develop the technology on their own. This thread has too much handwavium involved, I'm going to have to drop out because I've suspended disbelief as much as I can. The ASBs are calling.
Of course this thread has too much handwavium involved, but based off of what we know, it's only logical to assume this world would be unipolar. I'm running off the idea that Germany performed miracles on the Eastern front, and the U.S managed to land in Normandy and start pushing East when the Soviets and Germans were still duking it out near Moscow. The post-war borders would reflect a Europe dependent on the U.S, a Soviet Union having trouble even reaching their 1939 borders and struggling financially, industrially, and in terms of manpower, and a U.S that has allied or client states all over East Asia. Then, Soviet spy rings are somehow disrupted, and the U.S adopts a policy to try to contain the amount of people with nuclear weapons. It's really stretching things, but it's probably the best we have.
And no, I don't think there'd be some coalition to ostracize America, because that would be ridiculous. The whole world would be reliant on the American economy at this point, and Washington would never let a coalition form. Nor am I saying it would be bloodless, or that Washington won't push their agenda onto the world, of course the will. I'm just saying all of that is still preferable to a world where two superpowers promote increasingly more brutal regimes to fight each other to the death.
When a nation reaches a certain size and has a certain level of influence, other powers stop trying to form coalitions against it and start trying to appease it. Just look at Rome when it was transitioning from Republic to Empire. Or, as a better example, look at the British Empire in the 19th century, as other powers recognized they were the strongest Great Power.
First, it doesn't mean there is no fear of Communism. Funding insurgencies in the third world is a lot cheaper than large conventional or nuclear forces.
Second, it doesn't mean China allies with the USA. Even if you have a Nationalistic victory due butterflies, the Chinese government might decide that Asia for the Asians isn't a bad policy after all. So at the end of the day, Vietnam might play similar to OTL.
And even if it doesn't, there will be a lot of conflict still erupting in the world. In some cases, the USA would be able to uphold United Fruits Corporation profits with little casualties. In other cases, it might get involved in protracted affairs.
You are thinking in the premise that a weaker USSR means no conflict appears in the periphery. I don't think it's the case. Insurgencies and other conflicts are rooted in internal problems of the affected countries which get played by foreign powers. No nukes, and even a weaker USSR, doesn't mean those conflicts disapear nor that they don't get external backing.
Also, the USA can't go back to isolationism. It has too many economic interests across the world. At some point, some Chief of State, somewhere, is going to nationalize some American owned property, or tell Yankees to go home, or would otherwise feel perceived as less than ideal for the American government. And the USA will meddle.The Cold War put constraints to the USA use of military power. Those constraints don't exist in this scenario.
I'm assuming China allies with the USA and all that because I'm trying to make sense of the scenario given to us by the OP.
And I never suggested there wouldn't be conflict; just that there would be far less blooshed than OTL. What's worse: a conflict like Vietnam, or a conflict like the Gulf War? Situations like Vietnam will emerge, and you'll see a U.S that's much more willing to compromise and less hysterical about Socialist movements. Remember that U.S policy as a whole was very pro-decolonization, as freer markets meant more countries to trade with, and breaking up European colonial Empires increased the American's status.
So in actuality, the U.S would be less prone to interventionism than it was IOTL. They have the public to think about, who don't like long wars, and they can't be everywhere at once. Rather than a race to control as many countries as possible like there was with the SU and US, it's just whatever issues are important at the time in Washington will be addressed.
And the U.S is also less likely to have a culture so gun-ho about war.
And of course the U.S will defend it's "interests" in other nations, and generally trample over some countries' rights, especially in the Middle East and South America. But they did this IOTL too, and they'll be better about it ITTL without Communism inspiring so much fear and jingoism.
I cannot claim to have the same amount of knowledge that you probably have in american history, however, since the Monroe doctrine precedent, there was heavy interference and influence of the US in other countries, especially in Latin America. Sometimes it was for good, i believe that the US was the first country of relevance to recognize Brazilian independence when we were still negotiating with the UK and fighting off the few remnants of Portuguese loyalists, other times... well, it wasn't that good, like what you did to Cuba, and private intervention in Central America.
Here in South America we use "world police" not necessarily in Cold War context, it's mostly a derogatory term that we use thanks to our perception of heavy and often completely unnecessary interference of the US in our affairs, and the absurd demagogue language that your country (i assume) uses to justify that. But of course, i believe that in academic context that is technically wrong.
Of course that the ideological clashing amplified the perceived need by US public opinion that you really needed to support bad guys down South to keep the light of democracy flashing in the North. But the US doesn't have really a good historic before that.
I'd like to start by saying that U.S intervention, particularly in South America, was almost always a net negative and that we really fucked up a lot of countries and regions in the past. ITTL, the US would be likely to do this still.
But here's the thing; the subset of culture in the U.S that has developed concerning jingoism, hyper-nationalism, being the "World Police" is a direct result of the Cold War. Without the perceived need to stop the spread of Communism, and the feeling that we're the "defenders of democracy", this sort of thing won't be as strong as IOTL. It will still be there, but in this case, less is still "safer" as laid out by the OP.
Now, I could also go on and on about U.S intervention prior to the Cold War, led by business interests and some garbled idea of the Monroe Doctrine. This will still exist, absolutely. But again, it won't be as bad as IOTL, because the U.S will feel less threatened. Washington would be less likely to support crackpot dictators or murderous maniacs, and although they'll still exploit the world in general, it will be better than two superpowers sucking the earth dry in a bid to out-compete each other.