WHEN PRESIDENT John Tyler accepted an invitation to the launch of the USS Princeton on the Potomac River at Alexandria on Feb. 28, 1844, he had no inkling of what was in store. The launch of a major U.S. Navy warship and the demonstration of the world's largest naval gun were great reasons to celebrate. Tyler could never have anticipated that the day would end in both tragedy and romance.

The first vice president ever to become president--when President William Henry Harrison died in office--Tyler was dubbed the "Accidental President" and opinion was divided on how much power he should assume. When he used the presidential veto to block the creation of a U.S. Central Bank his entire Cabinet resigned (except Secretary of State Daniel Webster, who stayed on for a year to complete the treaty with Britain settling the Maine-Canada border). Tyler immediately assembled a new Cabinet.

Although it went through several more reshuffles, by February 1844 he had a full Cabinet: Secretary of State Abel Parker Upshur, Secretary of the Navy Thomas Gilmer and Secretary of War William Wilkins. They all shared Tyler's views on the big question of the day--slavery.

Slavery informed every issue, including the relationship between the United States and Great Britain. Although the Maine-Canada border had been settled, feelings between the two countries still ran high. Britain had abolished slavery and outlawed the slave trade and had taken to harassing American trading ships on the high seas. In the Northwest, Britain and the United States ruled Oregon in an uneasy alliance, and in the South they vied with each other for influence in the recently independent Republic of Texas.

Fearing that a British takeover of Texas would surround the United States with free territory to which slaves might escape, the Tyler administration hoped to bring Texas into the Union as a slave-owning state, thus strengthening its hand against the Northern abolitionists. They hoped to settle the Oregon and Texas questions without precipitating a war with Mexico or Great Britain. A warship that brought the U.S. Navy closer to the might of the British navy would provide the muscle behind U.S. diplomacy.