High Quality Content by WIKIPEDIA articles! Abel Parker Upshur (June 17, 1790 – February 28, 1844) was an American lawyer, judge and politician from Virginia. Upshur was active in Virginia state politics and later served as Secretary of the Navy and Secretary of State during the Whig administration of President John Tyler. Upshur was instrumental in negotiating the secret treaty that led to the annexation of Texas to the United States and played a key role in ensuring that Texas was admitted to the United States as part of the Union. He was among six people killed when a gun exploded during an official function on board the steam warship USS Princeton.