On September 19, 1796, the Philadelphia paper Claypoole's American Daily Advertiser printed a 32-paragraph letter addressed to the people of the United States, signed George Washington. It announced that he would not stand for a third term, and it spent most of its length on advice about what the country should avoid. Within weeks nearly every newspaper in the country had reprinted it.
He had worked for years. The first draft was by James Madison, written in 1792 when Washington had wanted to retire after one term and had been talked out of it. Hamilton reworked it in 1796 from Madison's text and from a list of points Washington gave him, and Washington revised Hamilton's version. The result is a composite, and the two men's hands can be seen in it: Madison wrote the opening and closing on union, Hamilton the sections on foreign policy, Washington the parts about his own errors and about why he was going.
The famous passages are about two things. On foreign policy it says that Europe has a set of primary interests which to the United States have none or a very remote relation, and that permanent alliances should be avoided, though temporary ones for extraordinary emergencies are fine. On domestic politics it warns against the spirit of party, which it says serves always to distract the public councils and enfeeble the public administration, and against the accumulation of debt and the overextension of the military.
The warnings were not abstract. In 1796 the country was arguing about the Jay Treaty with Britain, which the Democratic-Republicans called a surrender, and about the Genet affair and the French alliance of 1778, which the Federalists wanted to be rid of. Washington had declared neutrality in 1793 and had sent John Jay to London in 1794, and he had been attacked for both with a violence that surprised him. The address is in part a defence of that record.
What it became is different. For more than a century it was read as a prohibition on entangling alliances, and it was cited against the League of Nations in 1919, against the United Nations in 1945 in part, and in favour of neutrality legislation in the 1930s. That reading overstates it, and the address itself says commercial relations should be free and that treaties of a temporary nature are acceptable. Washington left office in March 1797 and died in December 1799.