The Ninth Amendment to the Constitution, included in the Bill of Rights, states that the people of the United States have rights that are not included in the Constitution. The framers of the Bill of Rights understood that the interpretation and viability of the Constitution would change over time, so designed it to be specifically elastic in an attempt to prevent future abuses of rights. 

The "three-fifths" compromise was a deal struck between Northern and Southern representatives to the Constitutional Convention in 1787. Southerners believed the full population of their states, including slaves, should be counted to determine representation in the House of Representatives. Northerners argued that slaves would never vote and that fully counting them would disproportionately represent the South in Congress. A compromise was agreed to with the following language, in Article I, Section 2 of the Constitution: "Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons." This clause was not taken out of the Constitution until the passage of the Fourteenth Amendment in 1868.

The Elastic clause states that the Federal government has the right to make any laws, even those outside of the ones specifically mentioned in the Constitution, if Congress deems the passage of these laws to be “necessary and proper.” As a corollary and counter to the Elastic clause, the Reserved Powers clause was added into the Bill of Rights as the Tenth Amendment. The Tenth Amendment states that any powers not reserved for the Federal government are the sole property of the States and of the People.

French exploration of the New World was motivated primarily by a desire to find a trade route to Asia. Much of the Eastern trade routes had been closed following the Ottoman Empire’s capture of Constantinople, and the French wanted to find a quicker route to Asia that did not involve passing through Ottoman territory or sailing around the horn of Africa. The French later founded colonies throughout the New World, particularly in Canada where they engaged in fur trading with the native population. 

Hernando de Soto was a Spanish conquistador who attempted to follow in his countrymen's path by exploring uncharted areas of North America. Beginning in Spanish held Florida, De Soto's expedition ventured across the present day Southeast of the United States. De Soto died of disease in present-day Arkansas, in 1542. His expedition continued into Texas and down towards New Spain (present-day Mexico).

After overthrowing a government seen as tyrannical in the Revolutionary War, the nascent United States of America adopted a loose agreement called the Articles of Confederation to govern itself. The Articles sat a single body, known as the Congress of the Confederation, with equal representation and no real executive authority. This light structure soon proved a burden to the young country, as they had no way to collect taxes, establish interstate trade, or raise any kind of national army. In 1787, delegates from all the states began meeting about revising the Articles, which eventually led to the writing and the adoption of the U.S. Constitution.

The Treaty of Tordesillas was an agreement between Spain and Portugal about how the newly discovered lands, ripe for conquest and empire-building, should be divided. Very little of the land had actually been seen by any Europeans yet, but essentially the Treaty gave almost all of the Americas to Spain, with a small section of South America (modern Brazil) reserved for Portugal, and almost all of Africa and Asia to the Portuguese. The Treaty was loosely respected for a time by both countries and is a massive determining factor in the culture, language and society of many modern nations around the world. 

Whether intentional or not, Eli Whitney's cotton gin resulted in an increase of slave numbers throughout the American South, as the southern economy became more heavily dependent upon upland short cotton.

In the era of America’s Founding Fathers, most prominent thinkers thought that it might take as much as a thousand years to settle the entirety of the continent under one national entity. Due largely to the invention and widespread construction of Railroads this was achieved in a mere few decades. Railroads helped promote trade across the continent and further afield – enabling goods from the Far East to be shipped back to the Eastern seaboard. It encouraged the growth of urban communities which could be much more easily sustained by railroad trade. And, not insignificantly, it provided for the first time a far easier means for tourists from the East to travel to places like Yosemite to witness the wonders of America’s, as of yet not established, National Parks—which in turn lead to much wider support for legislation to protect them. It did not, however, improve American relations with Native American communities—one might suspect that the removal of the massive boundary of space might have resulted in the reduction of the perception of Native Americans as an “other” group to be feared; on the contrary, it allowed Americans to move en masse to territories occupied by Native Americans, and made it much easier to keep supply lines reinforced. 

The Pony Express was known for it's speed and reliability, but the new telegraph lines, once complete, were much cheaper and more efficient. This development rendered the Pony Express obsolete in a mere 18 months.