Meanwhile Russia, with 1/8th the GDP, is rolling over us.
Shootin' wars ain't the only way to dominate.
And look at little Singapore. A country should rely on trade and soft power as much as military clout to protect itself. it's kind of hard for an enemy to bomb you when much of its own population is living and thriving within your borders. I can't imagine the family back home would be thrilled to learn than your compatriots are being bombed abroad.
Given how so many countries are so debt-ridden now, why not reduce redundancies and create an international police force of a maximum of a hundred thousand well-trained and equipped men. Maybe structure it as a kind of marine corps with access to small-scale nuclear weapons too.
If any country wants to supplement it with its own national force, by all means. But many countries in the world (and especially much poorer ones) would probably be happy to pay into such a force as a way to save money for their people.