Ships.
Sea transportation was just right at that time as it can carry loots, spoils of war , enough fire power to conquer new colonies, and also food and necessities for sojourners ,seafaring soldiers and traders. Even exploration of unknown territories was also done with the help of sea transportation.
This is both true and false the United States is a federal constitutional presidential republic. It is a joining of fifty smaller subject republic's known as states, they and the federal government imitate the Roman res publica style of government which is a further advancement of the Greek style. However the United States elects everyone in a similar manner by direct popular vote. This is the case with Governors, Representatives and Senators for the State legislatures and the United States Congress. The president is elected in a combination of the two. The populous votes for the person who they want to be president. After each state tallies its majority vote that States electoral college votes go to the winner of the majority in that state. It is very rare that a president wins both the electoral college and the popular votes. The electoral college decides the next president not the popular despite both being integrally connected to each other. This system ensures that States with a larger population cannot control the executive branch of the United States.
The Korean war never been called anything else that I know of
True the us was not a major global power until the end of ww1