"[Jefferson] got by the first year, but when the British were able to make a serious military effort in Va. in 1781, Jefferson's miserable failure as a leader was a vivid illustration of what happens to a society guided by a philosopher when it needs a 'man on horseback.'"
Not everyone is as kind to TJ as you guys are. We'll have to agree to disagree. And, I was wrong: it was not a court martial but a legislative inquiry.
For most of the war, Virginia was not a significant theatre of operation. During Jefferson's term as Governor, he did succeed in raising units that distinguished themselves where they were needed, mostly outside of Virgina. But they were put out of action in Charlston before the major action in his state. Jefferson did not hold a military commission. He was a civilian whose duties did not include being a "man on a white horse," as you put it -- that job was already held by three men in Virginia, namely, LaFayette, Rochambeau and von Steuben -- who all suffered numerous reversals, screw-ups and stalemates during much of 1781, in spite of the thousands of French and Americans at their command. In addition, there was Destouches who had similar misadventures on the water. Jefferson's term as Governor expired, in fact, in early June of 1781, and he was succeeded by Thomas Nelson. Most of the failures I alluded to above occured on his watch, not Jefferson's -- not that either of them had much control over military decision-making. You read all about it right here
Over the past few years, I've read most of his letters, to Adams and the 3 volume Madison set. Jefferson had only a fair intellect, in the pantheon of historical figures. His best qualities were his curiosity and his breadth of interest.