Attempting to analyze the causes and effects of war on Economies would require a rhetorical eloquence no less than those that authored the Federalist Papers, and, at the very least, the same volume of words. Fudging it all down to something as small as your typical The Atlantic commentary read is proportionally equal to asking a five year old to draft their own theories of government.
But, let's at least have a little fun with this, and perhaps attempt at sharing something of insight. Here goes:
A brief study of the history of the United States economy would generally yield a result looking no different in approximation than an increasing sine wave, generally increasing at an exponential rate. While there are upward trends and downward trends, of more-or-less of equal duration of time, the economy has been trending upwards since its inception. As for why it's continually trending upwards, no matter how complex the argument, it generally boils down to one simple word:
Our country maintains a relative balance between free market and regulation; between public and private sector; between state and federal governments; between taxable income and disposable income...and so on and so forth.
Naturally, given the general liberties our citizens possess, we from time to time will express our displeasure with the existing status quo. Displeasure among a proportion of the populace is inevitable. We all come from different walks of life and form opinions and biases preferring a bias against the balance in the direction of some extremism. As passionate citizens, we may attempt to swing the pendulum hard in a particular direction, as others naturally try to swing it in the opposite. We exercise this through electing representatives who share our views, posting our views online, speaking out at public meetings, attending rallies, drafting petitions, etc, etc. While these motions are a natural result of the state of government that presently exists, they generally do not threaten the state of government itself.
But, occasionally, it does. And it does, because factions within our society generate enough power among the citizens to disrupt the balance in favor of their zealous points of view. Thankfully, the founding fathers created a system of government that generally impedes factions. (To see a much more thorough and more eloquent analysis of this argument, please see Federalist Papers 9 & 10.)
I'm concerned that we may be living in one of those times. Our country is very unbalanced in its political view right now, and the inflammatory rhetoric from a zealous self-righteous minority faction is pouring fuel onto the fire. To make matters worse, one of those zealots is none other than our president. But, I digress.
When it comes to tax policies, balance is key. The United States economy fared very well following both wars, because both wars were funded by high income taxes. The United States economy also fared very well in the 20's, in the 90's, and before 2008, because income tax rates were very low, freeing up vast amounts of investment capital. And then the economies after all these booms crashed hard, much in part due to deregulation and poor investing. My point being this: Creating economic policies that directly reflect the present conditions with the intention of returning to a balanced economy are the keys to success. A zealous application of a tax policy for the sake of the tax policy alone will not contribute to economic success.