This one simple factor is why the US Allies won World War II

At first glance, it might seem obvious why Japan would choose to take on a country like the United States. While Americans were still struggling with the Great Depression, Japan's economy was growing and hot. Japan had hundreds of thousands of men in uniform and a string of military victories under its belt. The U.S. was a third-rate military power whose day had come and gone in World War I – and Americans weren't thrilled about another war.

But the Japanese seriously underestimated one important factor: The American Worker.

Up yours, Japanese Empire.

Judging the United States' capacity for war during the 1930s was Japan's fatal mistake. Sure, we'd had a little too much fun at the speakeasy during the 1920s, but we were poised for the most incredible puke and rally the world had ever known, and anyone looking for it would have been able to see it. Unfortunately, the Japanese were a little high on their own supply at the time. Convinced of Japanese superiority, they thought themselves nigh-invincible and that the U.S. would crumble if it needed to unify or die.

In reality, things were much different. The U.S. had twice the population of Japan and 17 times more tax revenues. Americans produced five times more steel, seven times more coal, and could outproduce the Japanese automobile industry by a factor of 80:1. The American worker had the highest per capita output of any worker in the world.

What's more, is we were one of very few countries willing to let women work in our very modern factories.

So don't f*ck with the Arsenal of Democracy.

Even before the war, U.S. industrial capacity was greater than all of the Axis countries combined. As a matter of fact, the United States' output was almost greater than all the other major powers involved in the war. And that was before the U.S. declaration of war allowed the President to take control of American industry. By the time the U.S. entered the war, the Lend-Lease Act had already pulled America out of its depression and was basically supplying the Allied powers with American-built equipment and vehicles as it had for years.

All we had to do was start using them ourselves.

As time went on, the U.S. economy was growing by 15 percent annually, while every other belligerent saw a plateau in growth or the destruction of their economies altogether. By the end of the war, American industrial output wasn't even close to overheating – we were just getting started.