Stanton had been an early critic of Abraham Lincoln’s presidency, but he remained in Washington after the start of the Civil War and served as an adviser to Secretary of War Simon Cameron. In November 1861 Stanton counseled Cameron to issue a report arguing that slaves should be armed to fight against the Confederacy. Coupled with allegations of corruption, this premature proclamation resulted in Cameron’s removal as secretary of war. Stanton would succeed him shortly thereafter in January 1862.
As secretary of war, Stanton acted swiftly to untangle the bureaucracy of the War Department. A shrewd strategist, he also seized the U.S. telegraph system and used it to control military actions and filter the flow of information to the press. Like many in the North, Stanton believed the war would be quickly won, and in the spring of 1862 he made a famous error when he mandated that all military recruiting offices be closed. He would later strongly support Lincoln’s decision to institute the federal draft law in March 1863.
A small man who suffered from severe asthma, Stanton was nevertheless relentless in his management of the war effort. Early in his tenure he issued an order canceling all foreign contracts for military goods, a move that helped bolster U.S. industry. He also revamped the transport system and made extensive use of railroads to speed the shipment of war materiel. One of Stanton’s most notable accomplishments came in September 1863, when he took a mere 10 days to coordinate the transport of 20,000 troops over 1,500 miles to reinforce Union General William Rosecrans at Chattanooga, Tennessee.
A staunch Unionist, Stanton was suspect of any military officers or public servants he thought might hold neutral or pro-Confederate stances. He was tireless in his efforts to arrest or remove those he viewed as disloyal, and during his tenure civilians and other figures deemed to have undermined the war effort were often jailed without charge. Stanton’s opinions made him no shortage of enemies during his tenure. He was particularly critical of General George B. McClellan and actively campaigned to see him stripped of his title as general-in-chief of the Union Army in 1862.
Although he had been critical of Abraham Lincoln’s early administration of the war, Stanton later joined Secretary of State William Seward as one of Lincoln’s closest advisers and even switched his allegiance to the Republican Party. He was a strong supporter of Lincoln’s Emancipation Proclamation and vehemently encouraged the use of black troops in the U.S. war effort. Lincoln eventually came to view Stanton as one of his most valuable assets, ignoring repeated calls from Stanton’s political opponents that he be removed from office. When Lincoln was assassinated in April 1865, Stanton reportedly said of the president, “Now he belongs to the ages.” Stanton would go on to manage the prosecution of the various conspirators involved in assassinating Lincoln, ensuring that they were tried in a military court.