Everyone should read George Washington's Farewell Address, and Federalist #10, what Washington feared the most.

In particular, Washington feared that geographic identities would serve as the foundation for the development of political parties. Indeed, this process had already begun with the emergence of the New England Federalists and Southern Democratic-Republicans. While we currently view partisanship as inseparable from the American political process, in the early republic, most condemned parties as divisive, disruptive, and the tools of demagogues seeking power.5“Factionalism,” as contemporaries called it, encouraged the electorate to vote based on party loyalty rather than the common good.Washington feared that partisanship would lead to a “spirit of revenge” in which party men would not govern for the good of the people, but only to obtain and maintain their grip on power. As a result,he warned Americans to guard against would-be despots who would use parties as “potent engines…to subvert the power of the people and to usurp for themselves the reins of government.”6

The greatest danger to the Union, though, stemmed from the combination of factionalism and external invasion. Washington explained that partisanship “open[ed] the door to foreign influence and corruption” because it weakened voters’ abilities to make reasoned and disinterested choices. Rather than choosing the best men for office, the people would base decisions on “ill-founded jealousies and false alarms,” and so elect those in league with foreign conspirators. To avoid outside interference, Washington advocated a foreign policy based on neutrality and friendly commercial relations with all.7

https://www.mountvernon.org/library/digitalhistory/digital-encyclopedia/article/george-washington-s-farewell-address