However [political parties] may now and then answer popular ends, they are likely in the course of time and things, to become potent engines, by which cunning, ambitious, and unprincipled men will be enabled to subvert the power of the people and to usurp for themselves the reins of government, destroying afterwards the very engines which have lifted them to unjust dominion.

Could someone explain what Washington is saying in this quote?

He's saying that political parties can be used to promote private interests, mainly to make it easier to make money by manipulating laws, instead of public interest (as in the interests of ALL the people, not just a few). For example, if you borrow money to buy a new car, if the bankers controlled the government and the laws, they might charge you VERY high interest rates. If the law, in the interest of you and other borrowers, made that illegal, it would be to the benefit of everyone. Unlimited interest rates would hurt everyone else, but help the bankers make more money for themselves. Or if the drug industry wants to charge higher prices in the United States than they do in Canada, the drug industry could get the law to prohibit U.S. people from buying cheaper drugs in Canada. That really is happening now. Political parties can be used for purposes like that, or Washington was afraid they could be.

If you still don't understand, please say so and I'll try again. :)

In this quote, George Washington is expressing his concern about political parties. He acknowledges that political parties can sometimes serve the interests of the public, but he also warns about their potential dangers. Washington believes that over time, political parties can become powerful tools for cunning, ambitious, and unprincipled individuals. These individuals may manipulate the system to gain control over the government, ultimately subverting the power of the people.

Washington further suggests that once these individuals attain unjust dominion, they are likely to destroy the very political machinery that helped them rise to power. In other words, they could undermine the democratic principles on which the political parties are based, leading to the abuse of power and potentially jeopardizing the rights and liberties of the people.

In summary, Washington cautions against the long-term effects of political parties, warning that they can be exploited by unscrupulous individuals and ultimately threaten the foundations of democracy.