The one foe that our Army can't vanquish is the budget process.
When we are at peace, nobody thinks the Army is needed and can safely be cut more than the Air Force or Navy.
If called to fight, if the Army loses a war nobody wants to use the Army again, and so it is subject to greater reductions than the other services.
And if the Army wins, the Army suffers from the peace effect plus nobody wants to pay the price of winning again, and so the Army is cut more than the other services.
But then, even though nobody plans to need the Army again because we don't want to lose a land war again, or don't want to pay the price of winning a land war again, or don't foresee any land enemy we might need or want to fight, we eventually need the Army again to fight a land war.
Oh well. Perhaps I should simply be grateful that Canada and Mexico don't pose a threat of invasion so we have the luxury of viewing the Army as something we hope we can shrink and pack away until needed to win a land war.