Though McClellan failed to destroy Lee’s army, his contribution was in many ways notable. In the 3 weeks after he was chosen for command on September 3, he provided for Washington’s defense, created a new field army, fought two major actions, compelled Lee’s evacuation of Maryland, and established Federal control of the Potomac River from Washington to Williamsport. That he was not a daring commander of Lee’s stripe cannot detract from these solid achievements. Lee, on the other hand, may have been too daring. Because of this he made two major miscalculations. First, his invasion of Maryland imposed a strain that his poorly equipped and exhausted army could not support; heavy straggling was the surest evidence of this. Second, he misjudged the capacity of the enemy to recuperate from the effects of Second Manassas and quickly put a reliable field army on his trail. He did achieve one of his objectives: The delay of the Federal armies in resuming major offensive operations in Virginia until the next winter. But the price was high and the South could not afford the kind of attrition suffered in the campaign. Casualties were so heavy in the Battle of Antietam that September 17, 1862, is termed the bloodiest day of the Civil War. Of McClellan’s 26,023 killed, wounded, and captured during the Maryland Campaign (including Harpers Ferry), he counted 12,410 at Antietam. Of Lee’s 13,385 casualties during the campaign, 10,700 fell at Antietam. _The War for the Union Takes on a New Purpose_ After Antietam there was no serious threat of foreign recognition or intervention on behalf of the Confederacy. And the repulse inflicted on Lee’s Army of Northern Virginia gave Abraham Lincoln the opportunity he had sought: On September 22—just 5 days after the battle—the President issued the preliminary Emancipation Proclamation. It declared that upon the first day of January next all slaves within any State or district then in rebellion against the United States “... shall be then, thenceforward, and forever free.” [Illustration: _Lincoln visits McClellan and his staff after the battle. McClellan is the fourth man to the left from the President._ Courtesy, National Archives.] [Illustration: _Lincoln and McClellan confer on the field of Antietam._] [Illustration: _The President reads the Emancipation Proclamation to his cabinet._ From an engraving based on the painting by Francis Bicknell Carpenter. Courtesy, Library of Congress.] With the formal Emancipation Proclamation of January 1, 1863, the war took on new purpose. In the North, and in many foreign lands, the cause of American Union had become one with that of human liberty. _Clara Barton at Antietam_