The Revolutionary War with Britain after British colonists were already in the US, sent by the British. Basically, they were being taxed on stuff like Molasses and Tea. They didn't want taxation from a country in which they had no representation in government. This was the reason for the Boston Tea Party. Then of course they formed their own independent country once they were free from Britain.
President Jefferson authorized Robert Livingston and James Monroe to purchase all the Louisiana Territory This agreement was known as the Louisiana Purchase. The purchase itself included land from fifteen present day states including portions of Arkansas, Missouri, Iowa, Oklahoma, Kansas and Nebraska, South Dakota, Montana, Wyoming, Colorado.
<span>Divisions over slavery in territory gained in the Mexican-American (1846-48). War were resolved in the Compromise of 1850. It consisted of laws admitting California as a free state, creating Utah and New Mexico territories with the question of slavery in each to be determined by popular sovereignty, settling a Texas-New Mexico boundary dispute in the former’s favor, ending the slave trade in Washington, D.C., and making it easier for southerners to recover fugitive slaves.
hope this helps</span>
Thomas more and Niccole Machiavelli
Russia, Ukraine, Belarus, Georgia
hope this helps