It started way before the Civil war. Half of Mexico was stolen in the 1840s, and the 50s were years of filibustering in Central America and planning for the takeover of Cuba. Back then, it was mostly the Southerners looking for new areas into which to expand slavery. One issue that in the US is seldom remembered is that Texan independence was jump started by the Anglo settlers refusal to enforce new Mexican laws banning slavery. The fact that the defenders of the Alamo were for keeping men in bondage, while the attackers were against it, doesn't go down well with those ideas of "Manifest Destiny" and "shiny city on a hill" that are loved so much across the Río Bravo.
Well, it wasn't really Teddy, but his predecesor, McKinley, but I understand what you are driving at. It's always kind of funny to remember that 1898, the very year in which the US fought 'to expell tyranny form the hemisphere'... was also the year of the great race riots (read lynchings of African-Americans) in Atlanta, soon followed by others in New Orleans and NY, as well as the year in which the Supreme Court ruled the infamous Williams v. Mississippi, just 2 years after Plessy v. Fergusson (the former ruling approved black discrimination from the polls, effectively crushing the XVth ammendment; the latter sanctioned Jim Crow seggregation, waving aside the XIVth's Amm. equal protection clause... makes one wonder if the Civil War was worth the carnage!). That very same decade, some 1900 people were lynched in the US, of which about 90% were blacks (a couple of Jews thrown in just for variety), including 50 women, of which about a dozen pregnant.
Indeed, the US was standing up to tyranny...
Well, in the 1980s, a final investigation by the Department of the Navy concluded that the explosion took place 'inside' the ship... so some party or other certainly furnished the pictures...
The US was so keen to liberate the Cubans, that they banned them from the peace negotiations. They kept Cuba for a couple of years (Puerto Rico to this day), and only left after forcing the Cubans to accept the Platt ammendment into their constitution, granting Washington the right to interfere whenever it deemed it fit (as well as the use of Guantanamo for an indefinite period... Gitmo was never meant for freedom!). Of course, the worst came in the Phillipines, where the Filipino rebels were freed from the Spanish... er.. only to be crushed in an often forgotten but truly vicious war (1899-1904), which saw the Marine 'liberators' turn into concentration camp butchers). (BTW, Filipino civilian war deaths are estimated anywhere between 200,000 and 1,500,000. Source: wikipedia).
But, appart from mere triffles like these, US history has been an unbroken yellow brick road towards Freedom on a City upon a hill. And don't anybody dare doubt it (we've got Predators).
Seems you harbor no illusions about the American dream and the Manifest Destiny.
Still, the US story is inspiring at least to some extent and in some instances.
I understand what you are saying, but I think that that sorts of expansion, including Texas was typically and originally American, "let's grab some land for ourselves, our private individual interests, and stick our banner in it". It was comprised in the "Gone to Texas" slogan and the Davy Crocket words "You may all go to hell, and I will go to Texas". Note the "I". The Anglo-saxon settlers prevailed and that was it, still more or less a highly individual affair. But imo, only after the civil war carnage and the industrial revolution that followed the times saw the organized effort to overthrow foreign governments or to install puppet regimes, that was a lesson learned from the war, how to collectively and in an organized manner mobilize the public for your cause, with coordinated propaganda, how to impose political will and advance economic interests. South was in fact conquered, occupied and a puppet regime was installed there, composed of northern "carpetbaggers", and southern collaborationists. Sadly, the black population, mostly poor and uneducated for obvious reasons, and now even without their masters who at least provided for basic needs, were left high and dry and they didn't manage to articulate their position and interests. Under those circumstances, they served mostly to advance northern interests... that's the point where racial hatred in the south was truly born... before that the southern whites, although surely racist did not have reasons to hate or envy blacks... When so called reconstruction was over, and southern whites inevitable regained their say, i.e when eventually the southern democrats and the northern republicans politically buried the hatchet, the blacks were the first to pay a heavy price...and even today there are some traces of it, with all the things they have had to endure.... it took 100 years
(!) to again have an African American senator (or congressman, I forgot, I should check)from a southern state. It happened only in the 70s, less than 40 years ago, quite recently. The time after the Civil War until the Spanish War is very interesting, it witnessed major changes, with burning racial issues and the Jim Crow laws that followed and proclaimed "separate but equal" policies to avoid the constitution. Jim Crow is another unfortunate son of the Civil War, typical one that was waged for noble cause on the surface and for greedy reasons in the core. It was a bad war, especially traumatic for the entire US, to this day it's the war with the most American casualties, that's history and there are many interpretations of it, of course.
The thing that we must admit when we talk about the US, is there was always this will among ordinary people to improve, to go for more and demand better for themselves. It's like ok, we are far from perfect but at least we are trying to move in the right direction. There is still this sense in the US, but after years of shaping the public opinion in all possible ways, the US elite seems to have come to believe in their own BS, and that's a dead end. Remedy: Back to the Roots - in a positive sense of - pursue your own individual happiness, live and let others live, maybe they are cliches but I've always liked that kind of simple and powerful statements. Maybe this has gone off topic, I hope the mods will not delete it, it's still interesting, imo.