In this case we did know better, because the Monroe Doctrine and other doctrines have been aggressive. The Great White Fleet was a wrong when sent to frighten Japan into opening trade. By that time the government had departed from a defensive position and was wielding sway. The populace had come to believe that was correct behavior, because we had had so much success, so much unexpected success. The USA was once seen by many as a risk, as something which shouldn't have worked out but did -- perhaps miraculously.
From the time of Independence through most of the 19th century, the U.S. had confined its aggression to its own immediate vicinity. True, we did send out a fleet to Japan to open up trade, but I don't think we had any serious intention of invading or colonizing that territory. A big turning point was the Spanish-American War, after which we gained Puerto Rico, Guam, and the Philippines, which is how we got a foothold in East Asia and made us a player on that continent with the European colonial powers which had already been operating in that region (along with Japan, which was also trying to build up their own empire at the time).
But even then, we were still a junior power, whereas Britain and France were the big giants in the world at the time.
In hindsight we can see that it was a mistake to move away from the founding principle of 'Don't tread on me' or 'To provide for the common defense'. Now here we are, stuck in the middle of the road, promised to be one of the knights of the round table for the foreseeable future. We've got bases all over the world, a military bill that could build a new planet, leaders of other nations worried about what we're going to do next or who we'll elect next. We're starting to see that we can't sustain all of this influence and probably shouldn't try.
Another mistake was in the belief that we could (or should) become a world colonial player, like Britain and France were at the time. Just because they had empires didn't mean that we should try to attain one, yet that was another mistake (and by that time, most of the world was already sewn up, so all we could do was grab leftovers from other nation's empires, such as Spain's).
We were a major power by the time of WW1, but not quite yet a superpower. Britain and France became allies mainly because both were worried about upstart Germany trying to muscle in on their action. Americans became worried, too, because the German Kaiser was a megalomaniac and a reckless fool (not unlike some of our own national leaders).
After WW1, the best thing for the world would have been for the European powers to withdraw from all of their colonies and for the US to withdraw from the Philippines. The fact that they waited another 30-40 years was another bad mistake.
I don't quite agree on this, because the Soviets were quite evangelistic and went about converting other governments to communist dictatorships. They fomented many revolutions, many bloody ones. They had people here talking about a revolution in our country, but this was blocked (perhaps illegally) stopped by our new FBI agency. USA could easily have been put into another civil war or other bind by agents of the USSR. They were indeed out to destabilize our capitalist (and to them evil) union.
The Soviet government was comprised of revolutionaries who came from humble origins and oppressed under a monarchist dictatorship. They were aware of other working class and/or oppressed peoples in other countries, so they saw themselves as natural allies. If there were revolutionaries in other countries and they asked for help from their Soviet comrades, then they wouldn't have been forcibly converting anyone as much as assisting those who had already converted on their own. And why shouldn't they? If the US or Britain or France was colonizing or otherwise exerting hegemonic control over their country, then it's natural that there would be local inhabitants who might want to fight back and liberate their country from colonial oppression. If the Soviets took advantage of that opportunity, then the fault would still be ours for failing to uphold principles of freedom and democracy in the areas of the world where we held influence. South Korea was not a free country. South Vietnam was not a free country. Cuba was not a free country prior to the Communist Revolution in that country. China was not a free country prior to their Communist Revolution. Same for Nicaragua, which was ruled by a brutal US-backed dictatorship. Other countries we've supposed "protected" from Communism include Iran, Chile, Guatemala, El Salvador, Honduras, and many others which have some of the worst human rights record in history.
I seriously doubt that they ever could have fomented a civil war within the United States. Hoover's FBI and other McCarthyites were constantly paranoid about such a thing, but it was an unfounded fear. If we ever came close to something like that, it wouldn't have been due to Communists. Rather, it would have been due to the paranoid anti-Communists and their warmongering and other interventionist activities which more Americans were becoming aware of and expressing their sharp disapproval of such activities. The warmongers blamed Communists for the anti-war movement, but I say it was the obsessive anti-Communists who contributed the most to the internal divisions facing America at the time.
