This was never declared as a specific plan or objective, but has been almost openly pursued by some US presidents and there is evidence that the idea of creating one super-nation may have been in the back of the minds of at least a few of the founding fathers when they created the US constitution. Thomas Jefferson, in a letter to James Monroe, wrote that "it is impossible not to look forward to distant times when our rapid multiplication will expand itself beyond those limits, and cover the whole northern, if not the southern continent."
The plan never played out but the notion lived on and through a distorted sense of democracy it might be considered justifiable to expropriate the name "American" as a moniker for exclusive use of the USA. While the number of states involved in the union is a majority of the separate states in all of America, the union represents a majority only if it is agreed that each state has only one vote, but it is far from a majority of all the people in the area.
A search of "population of America" in Google returns a result for the population of the United States of 319 million whereas the population of South America is 387 million, Central America is estimated at some 47 million and we still haven't included the populations of Mexico and Canada which add another 140 million to the equation. The total population of the Americas is well over 893 million of which 319 is barely over a third.
The use of the term "American" is widely rejected throughout Latin America and is considered by many to be an inappropriate misuse of the term to describe a person or any thing which is specifically attached to only the United States. In Spanish the denomyn for a US citizen is "estadounidense," and the official Spanish dictionary states its view quite plainly:
But the use of americano to refer exclusively to inhabitants of the United States should be avoided; this abusive usage is explained by the fact that U.S. citizens often use the abbreviated name América (in English, without an accent) to refer to their country. One should not forget that América is the name of the entire continent and all who inhabit it are americanos. Translation from WikipediaIt is clear that anyone from the US who wants to make friends with others in the rest of the Americas, would be wise in employing another term and although they may have a long list of reasons to take pride in the country where they were born, they might reconsider the word they use when that word, in itself, reflects a dream that has never been realized.