[quote=@BingTheWing]
[@Dinh AaronMk] Not always - America came out of both the first and second world wars a powerhouse. War boosts the economy of the victor (if they've never been invaded themselves, of course), or motivates struggling countries to do so (e.g West Germany's Wirtschaftswunder).
[/quote]

Not necessarily.

Big war-time spending is followed rather immediately by sudden economic slumps. In the time-frame this RP is set after the war, folk should be in a post-war recession. In some cases they'll be on their way out; but that's the thing that's forgotten: the industrial shift from a war-time economy to a peace-time economy means that when the change happens there'll be a period of a slow, doggish economy.

What the world wars did for the US was to clear foreign competition. After both World Wars actually. With Europe crippled at the end of the first war and the second the US could work its way into selling product into markets with high demand and little to no ways to supply the demand. This rose the value of American commodities and when the economy came back to peace-time production the value of the US supply market rose sharply.

There were other issues at play too in each case. The Great Depression underscores the negative side-effects of going on a relentless supply spree and a certain lack of long-term foresight into what'd happen when supply breaches demand, Calvin College's belief in doing absolutely nothing certainly didn't help in mitigating the future disaster of an inevitable depression; one which was made as massive as it was because the US was the only functioning economy. Europe too couldn't afford to keep on the US tit either, since at the time the US owned a disproportionate supply of the world's gold and wasn't using it, so the old power-markets of the world were becoming hugely impoverished compared to the soaring wealth of the US.

A post-WW2 crash following the boom of the fifties was probably in part avoided because of US spending on support in Europe which became one of the earliest aspects of curbing the growth of the Soviet Sphere by keeping the western European populace from being so impoverished they turned to Communism. But this spending made sure that the UK, France, Western Germany and so on had enough capital flowing through them that they could spend it on buying American products to help fuel the American economy.

This doesn't mean even then the US economy grew consistently, Eisenhower had to deal with regular recessions and during the US post-war years industry began to take on the basic philosophy of the post-Pearl Harbor military: decentralize itself. But that's a whole other story.

War for the sake of Economic Growth is a pretty bad philosophy. Either a mission like Vietnam becomes morally questionable to outright deplorable, or like with the second war in Iraq and Afghanistan we get a total economic meltdown at home. But the underlying economic problem with war is that it creates false growth. All the product that's made never comes back to the people. It's all used up in explosions and fire and never to benefit at-home development. Two world wars close together would be absolutely devestating to worker populations and available resources  that might otherwise create growth.