After Early and Breckinridge (who was now able to ride a horse) chased Hunter more than sixty miles away from the city, Lee ordered them to clear the Union forces from the Shenandoah Valley, then cross into Maryland and probe the defenses of Washington, D.C. Union forces' only serious attempt to turn back the expedition came at the Battle of Monocacy on July 9. Confederate troops were delayed, but ultimately prevailed and continued toward Washington. They were defeated at the Battle of Fort Stevens on July 11–12, partially with reinforcements brought in by the United States Government with the time gained from the Battle of Monocacy. Since Lincoln was watching the fight from the ramparts of Fort Stevens, this marked only time in American history in which two former opponents in a presidential election faced one another across battle lines. Following the battle, Early decided to withdraw rather than assault the well-fortified federal capital. Early and Breckinridge were able to hold the Shenandoah Valley through July and August, but on September 19, 1864, Philip Sheridan forced their retreat at the Third Battle of Winchester. Responding to General John Brown Gordon's admonition to be careful in the fight, Breckinridge responded, "Well, general, there is little left for me if our cause is to fail."