High Quality Content by WIKIPEDIA articles! David Davis (March 9, 1815 – June 26, 1886) was a United States Senator from Illinois and associate justice of the United States Supreme Court. He also served as Abraham Lincoln`s campaign manager at the 1860 Republican National Convention, along with Ward Hill Lamon, one of Lincoln`s former law partners who served as the President`s primary bodyguard during the Civil War. Davis and Lamon, along with another Lincoln associate, Leonard Swett, helped engineer Lincoln`s nomination, according to the 1949 doctoral thesis Ward Hill Lamon: Lincoln`s Particular Friend, written by Lavern Marshall Hamand at the Graduate College of the University of Illinois.