America the nation was founded in the year 1776 after 13 British Colonies in North America declared independence in the North American Continent. Their key grievance was taxation without representation.

This declaration of independence was a paradigm shift and catalyzed the new American Nation

“When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.

“We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.—That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed,—That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness ( Source Wikipedia)

 A war was fought for 7 years and they finally achieved true independence in 1783. After that the country expanded west through conquest and land acquisition to reach the Pacific Ocean.

 A civil war was fought in 1861 to 1865 after the Southern States decided to secede from the Union. The war lasted for 4 years and led to the defeat of the Southern States but led to a stronger federal government.

The after effects of the war and the reconstruction period resulted in a boom in trade. Between 1865 and 1898, coal production rose by 800 percent and railway track mileage by 567 percent. By the middle of the 1880s, the United States had surpassed Britain as the world’s leading producer of manufactured goods and steel. 

Technological innovations, such as steamboats, passenger trains, and factory machines, transformed the United States from an agrarian country to an industrial one and produced newfound prosperity that enabled U.S. expansion across North America (Source  (cfr.org))

America began territorial oversea conquests by the turn of the twentieth century, the United States controlled territory spanning ten thousand miles from Puerto Rico to the Philippines. Its economy had surpassed the United Kingdom’s to become the world’s largest, supercharged by increased production of steel and the adoption of new sources of power like oil.

It boasted a powerful—and tested—navy, which could defend U.S. interests both in the Americas and now further afield. Indeed, the United States sent over a thousand marines to Beijing in 1900 to help put down a domestic uprising that threatened U.S. commercial interests.

Two World Wars cemented America’s Leadership position in the World. The first and second world wars left America as the leading economic and military power in the world. The USD Dollar became the World’s defacto Reserve Currency which gave America a distinct advantage in international trade.

America was the production hub for the Allies during the 1^st and 2^nd World War. It’s industrial might was transformed to produce the necessary war machinery and resources. This cemented it’s position as the leading economic power in the world.

This is a position it holds to this day. This all emanated from the Declaration of Independence.