It's easy to forget how interconnected the past is. All too often we study it as a set of discrete episodes rather than as a flowing river of time.
I knew that the American Revolution was among the causes of the French Revolution, both as an inspiration and because France's war expenditures led to a financial crisis. But until I read Fusiliers (Mark Urban, 2007) I hadn't fully considered that the army of Wellington was only about 30 years removed from the army of Cornwallis.
By focusing on a single regiment that served all the way from Lexington and Concord to Yorktown, Urban explores the reality of the British army--as opposed to the caricature of redcoated automatons we learned about in school--and how it changed in response to the challenges of the Revolution. If anything, the army improved considerably. It just didn't do them any good, because it's pretty much impossible to hold a large, hostile territory far from your home base with a small force, no matter its quality. The British effort was probably doomed from Saratoga onward, and certainly was once France entered the war. But the tactics they adopted to go on winning battles even as they lost the war ultimately bore fruit in the Peninsular War and at Waterloo.
Incidentally, I'm also reading a collection of Wellington's wartime correspondence. In one letter, he attributes just about everything that went wrong (from his perspective!) from 1776 on to party politics in England--the loss of the American colonies, the French Revolution, the rise of Napoleon, etc. His thesis seems to be that if the British powers-that-be had put country first instead of party, everything would've turned out differently. Who knows, maybe he's right. He did live through it all, though he was only six when the American Revolution started. Still, if I'm right about Saratoga, that wasn't a political blunder. Howe didn't march to reinforce Burgoyne, and so the Americans had a three-to-one advantage. But, if the British had been willing to come to a quick accommodation at that point instead of stretching the war out, the French would've stayed out of it, and then who knows how the next few decades would've turned out? Somehow I doubt that's what Wellington had in mind, though, because that's a Whiggish approach--it was the Tories, and especially the king, who wanted to continue the war. And even if Wellington didn't admit it, I'm pretty sure his non-partisan world would've involved everyone agreeing with the Tories. I love the man, but he had some obnoxious political views. (Stupid space-time continuum, because I'd dearly love to actually argue this one with the real Wellington instead of just shaking my head at the letters he left behind and quoting Barack Obama at him about how ALL of us love our country.)