Why did Washington win? Because:
"Washington scores highly as an enemy of Britain on three key grounds: the immense scale of damage he inflicts upon Britain's Army and Empire – the most jarring defeat that either endured; his ability to not only provide inspirational battlefield leadership but to work with civilians who were crucial to sustain the war-effort; and the kind of man he was. As British officers conceded, he was a worthy opponent." - Stephen BrumwellI'm kind of curious now to start looking into something like this for America. I'm inclined to want to include British from the War of 1812 or the Revolutionary War, but in the Revolutionary War, they got rotated through often, and were hobbled due to geography and logistics. I also don't know: Can we count Lee? If we can, I think if we put it to a vote, he would win, hands down. He probably proved the greatest existential threat to the Union, but it seems unfair.
World War I, I'm hesitant to really call out any commanders on the other side. America entered fairly late, and we again did not really face a direct threat to the main land. In World War II we have Admiral Isoroku Yamamoto, who probably posed the greatest military threat to America. The land war in Europe, while having some great German commanders, really pales in the threat it posed to America compared to the Pacific Theater.
There are the Indian Campaigns, with, I think, specifically Tecumseh, Sitting Bull and Crazy Horse being potential candidates that I can think of without doing too much research. When we get to Vietnam, I don't remember even being taught the names of the Communist commanders, but with a bit of Google, I think Võ Nguyên Giáp is recognized as the most influential Vietnamese commander.
I feel like the Gulf War and the current operations are a bit too recent to really measure, which may be part of the historian's fallacy in me. But, I wanted to present my thoughts. Probably the weakest are in the Revolutionary War era, where I can see some making an argument for Gen. Howe; taking New York City and Philadelphia were huge blows. In fact, after writing that, I feel stupid and revise my previous statement. Howe is definitely a contender.
I've probably missed some generals or overlooked a conflict. For example, I'm not sure if we should consider the War for Texan Independence. I'm pretty sure the answer is a flat out no, since that ended in the Republic of Texas. The Mexican-American War clearly belongs, but Santa Anna really isn't on the same level that the other commanders I've listed above.
So, let's get nerdy and see who else I've missed. Because I'm feeling really, really dumb for not including Howe. But not dumb enough to have revised my draft to include him in the first place. I was initially going to just save this link for the Friday link round-up, but then I realized I had... a lot to say. So, here it is.