My plan would probably boost the need for spending on social support for the young, since the size of the population of children would grow. But the point is those kids would then grow up to be adults, and assuming we didn't skimp on the support they needed to become healthy and productive, they'd then pay back that support many times over in the course of their productive careers.
No, and no. I don't know anyone who is anti-military spending. The question is simply one of levels. Should we spend three or four times as much as the next-closest country? I'd say no. And pretty much every other country in the history of the world has likewise said no. Hell, even the US said no through most of our history. For example, even at the height of the Reagan era's military over-spend, we didn't spend anywhere close to three or four times as much as the next-closest country. Yet, these days, we're supposed to pretend that anyone who advocates for a merely Reaganesque multiple of the next-closest country's spending must be anti-military spending. That's silly.
Also, this isn't about helping our allies. Again, no country before us in history thought you had to spend three or four times as much as the second-highest-spending country in the world in order to help the allies. This current spending level isn't about doing our part to work with other NATO nations to defend our common interests against foreign aggression. It's about having enough excess that we can kick over multiple regimes at once, on a whim, with little or no significant help from allies. That's an absurd level of spending, and ultimately a self-destructive one, in that it lures us into conflicts that are actually counter-productive to our security interests (such as the idiotic Iraq conquest that destabilized the Middle East and undercut America's political capital and credibility around the world).
As you probably know, back in the 1950s, the US wasn't spending anywhere close to three or four times as much on its military as the next-closest country. It was more like 40% more than the next-closest country, rather than 200-300% more.
https://nintil.com/2016/05/31/the-soviet-union-military-spending/
We can continue to support key allies, with the assistance of other allies, as we did in the past, with vastly less than we currently spend.