Answer:
The American government has three branches. You probably knew that. The executive branch is focused on daily administration of the country and is headed by the president. The legislative branch makes laws and is encompassed in the US Congress. The judicial branch interprets and upholds the law under the Supreme Court.
So, we've got these three branches, and each one has powers over the others to make sure that no one group can ever be too powerful. Think of it as a political version of rock-paper-scissors. President vetoes Congress, Congress undermines Supreme Court, Supreme Court overrules president and Congress, paper covers rock, rock breaks scissors, scissors cuts paper.
This delicate balance of power is written into the US Constitution, but it's actually changed over time. None of the three branches looked the same in 1787 as they do now, but as long as they changed together, no branch became more powerful than the others, and the game continued.
The main enemy of the french would be the British
Washington, d.c., although it is not a states capitol because the District of Columbia is not one of the 50 states.
The westward expansion era in the United States was one of great importance, as it helped to create the shape of the United States today. One of the reasons acquiring land was important was because it would help to complete America's manifest destiny. Manifest destiny is a term that states that it was America's god- given right to control all land from the Atlantic to the Pacific Ocean. This belief that it was supposed to be America's land caused them to buy land (like the Louisiana Purchase from the French and Florida from Spain) and even fight for it (Mexican-American War- results in US getting Arizona, California, Utah, etc.).
Besides completing America's manifest destiny, acquiring this land allowed the US to gain significant natural resources. A perfect example would be in California. After gaining California from Mexico, gold was found. This lead to the California Gold Rush of 1849. Finding this valuable commodity lead to a huge increase in the population of California and it gave the American economy a boost.