William McKinley (born William McKinley Jr., January 29, 1843 – September 14, 1901) was the 25th president of the United States from 1897, until his assassination in 1901. During his presidency, McKinley led the nation to victory in the Spanish–American War, raised protective tariffs to promote American industry and kept the nation on the gold standard in a rejection of free silver (effectively, expansionary monetary policy). That September, McKinley's regiment was called east to reinforce General John Pope's Army of Virginia at the Second Battle of Bull Run. The 23rd was the first regiment to encounter the Confederates at the Battle of South Mountain on September 14. After severe losses, Union forces drove back the Confederates and continued to Sharpsburg, Maryland, where they engaged Lee's army at the Battle of Antietam, one of the bloodiest battles of the war. The 23rd was also in the thick of the fighting at Antietam, and McKinley himself came under heavy fire when bringing rations to the men on the line.