The word "campaign" has its origins in 17th-century battles, the term referring to an army's field operations. By the beginning of the 19th century, "campaign" took on its current political meaning. And 150 years ago, it was aptly applied to both.For on June 8, 1864, the delegates of the National Union Party, a hastily assembled group of Republicans and politicians known as War Democrats, gathered in Baltimore for its nominating convention.