Does it have to remain the United States, or, as long as the USA wins the ARW, can it become an imperial/autocratic state? If the US still has a democratic government, I can't see total conquest of North and South America in the cards. There would be no motivation for said conquest.
M A N I F E S T D E S T I N Y
I think there are a lot of people ITT who're unjustifiably discounting the cause of America's changed attitude at the turn of the 20th century.
A lot of Americans wanted to annex Cuba, as far back as the Revolution. And a lot of people lay blame for that change on the rhetoric that Americans used to incite rebellion against Spain. ("Freedom! Independence from colonial overlords!") But, and
more importantly, the vested economic interest certain people (like Senator Henry Teller) had in sugar plantations in Hawaii led Congress to pass the
Teller Amendment:
The Teller clause quelled any anxiety of annexation by stating that the United States "... hereby disclaims any disposition of intention to exercise sovereignty, jurisdiction, or control over said island except for pacification thereof, and asserts its determination, when that is accomplished, to leave the government and control of the island to its people."
The proposed amendment gained support from several forces: "... those who opposed annexing territory containing large numbers of blacks and Catholics, those who sincerely supported Cuban independence, and representatives of the domestic sugar business, including sponsor Senator Henry Teller of Colorado, who feared Cuban competition." (A significant import tariff on foreign sugar would be removed should Cuba be annexed.)
The rhetorical justification for the Teller Amendment - America's alleged commitment to independent governments nearby - belies the true reasons for America's Cuba policy.
If a POD could change the economic situation in Hawaii, then Cuba (which has magnificently fertile sugar and tobacco plantations) would be economically much more appealing to American business interests. And therefore, much more appealing to American political interests.
That way, America wouldn't double down on the independent government line after the SAW. Maybe they spin Cuban annexation as "American constitutional democracy is true freedom!" or something like that.
Contributing to this scenario is America's nostalgia for the "good old days" after the
closure of the frontier in 1890 and the subsequeny development of
Frederick Turner's popular "Frontier Thesis" in 1893. Further, the fact that the Civil War ended decades ago terminates the slave state / free state tensions that barred
continued American expansion into Mexico after the Treaty of Hidalgo Guadalupe.
Combine these three elements together: frontier nostalgia, a refutation of Teller Amendment rhetoric, and the realization that continued expansion into Mexico wouldn't make slave states more numerous . . . And we get continued M A N I F E S T D E S T I N Y into the 20th century.
At the very least, that can lead to the USA conquering everything in North America, except perhaps Canada. (The only POD I can think of for Canada is "
General Richard Montgomery doesn't die and wins the Battle of Quebec in 1775." Oh well.)