This question originally appeared on Quora, the knowledge-sharing network where compelling questions are answered by people with unique insights. You can follow Quora on Twitter, Facebook, and Google Plus.
Answer by Stephen Tempest, qualified amateur historian:
The Kaiser would laugh himself silly at the sight of his two great Anglo-Saxon rivals destroying each other in a fruitless war that neither of them could win decisively.
Beyond that, it would depend on what exactly the war was being fought over that would determine who “won.” Neither the U.K. nor the U.S. had a big army in 1910. The British army was marginally larger, but both it and the U.S. Army were still nothing but colonial police forces by continental European standards. They probably had about the same level of combat experience thanks to the Boer War and the Spanish-American War, as well as similar levels of equipment and technology. In naval terms, the Royal Navy was clearly superior—larger, more modern and better-trained—but the gap was probably not wide enough to be decisive.
When it comes to resources and manpower, the U.S. had about twice the population of the U.K. (or 50 percent more if you also include the “white dominions”), and produced twice as much coal and four times as much steel. The American demographic advantage would be overwhelming if it had the time and political will to mobilize its resources for total war.
India might be a wild card here if the Indian people could be induced to rally to the British cause and mobilize a mass army of their own. (Cue an image of an American colonel in a fort in Kansas being told by a scout, “Sir, the Indians are attacking!” and marching out his troops to meet an incursion by 300 Cheyenne warriors, only to meet instead 300,000 Sikh and Maratha infantry and Bengal Lancers.) But I’m not sure what concessions the British would be prepared to offer in return for help on such a scale.
From a strategic perspective, it’s unlikely that the British could defend Canada and equally unlikely that the Americans could defend Hawaii or the Philippines—though given the technology of the era, the campaigns would be likely to be slow, with trench warfare, barbed wire, and machine guns bogging things down to a crawl instead of the rapid advances both sides would probably anticipate. The Caribbean would probably be the scene of several bloody naval clashes; although the Royal Navy is larger overall, the U.S. Navy would have the advantage of shorter supply lines.
After that there would be a stalemate. Neither side would have the capability to attack the other’s homeland. It would settle down into a war of naval blockade and commerce-raiding until the diplomats sat down together and called the whole thing off.
If Britain had gone to war with the USA in 1910, who would have won? originally appeared on Quora. More questions on Quora: