From March 17 to September 7, 1862, Wadsworth commanded the Military District of Washington. During the preparations for Maj. Gen. George B. McClellan's Peninsula Campaign, Wadsworth complained to President Abraham Lincoln that he had insufficient troops to defend the capital due to McClellan's plan to take a large number of them with him to the Virginia Peninsula. Lincoln countermanded McClellan's plan and restored a full corps to the Washington defenses, generating ill feelings between McClellan and Wadsworth. Seeing no prospects for serving in McClellan's army, Wadsworth allowed his name to be put into nomination for governor of New York against antiwar Democrat Horatio Seymour, but he declined to leave active duty to campaign and lost the election.