I've joked in past threads that it was in fact Lew Wallace who saved the Union, but I'm only half kidding. I went to the Civil War Institute's annual conference at Gettysburg College in June. A professor from the U.S. Army War College, Christian Keller, participated in a "lessons learned" session with respect to the Civil War.
He said that although it is mostly irrelevant to today's military in a tactical sense, they do still teach it from an academic standpoint and that all of our military service academies teach Early's Raid on Washington, specifically.
The Battle of Monocacy was hugely important in slowing Early, even though Wallace was whipped. The latter bought time for Grant to re-garrison Washington and save it. This is a huge, huge, 'what if' and Wallace gets the credit, in my view.
Thanks for the great pictures!