Oh, no alternative proposed. The US has lost 10+ trillion to what amounts to an unaccountable budgetary black hole, however, and limiting the awful dingleberry NGOs and private contractors and horde of companies and people that exploit the need for miltary R&D is a good thing.
The US should definitely keep doing R&D, the tech that comes out of DARPA has lots of downstream benefits beyond military applications. We should continue producing the best tech in the world, and explore all sorts of skunkworks and moonshots and crazy tinkering. I agree with "peace through strength" - be too dangerous to abuse, and if shit goes down, be the one who decides who wins and loses.
We don't need a corrupt military industrial complex, endless wars, private contractors, NGOs, nepo-grifters, and all the rabble that have abused the lack of accountability to make themselves rich, or inflict unrest on other countries, or manipulate bureaucracy for political gain, and all that jazz. Basic things like "department of war" naming fall in that direction, from my perspective. Simplify, cut, use blunt truthful language, and figure out how to hold them accountable going forward, at the very least, and at best, figure out how to claw back the trillions, or figure out where it went. You don't need to alter the underlying mission at all, really.
See, there's this notion that the US is a bad guy, and they point out all the casualties and conflicts and collateral damage and say "see, we're the baddies!" They never account for the context. Some of it is as simple as pointing out that if we hadn't killed all those german nazis, and sought pacifism and peace at any price, we'd all be speaking German. Some legitimate atrocities have occurred, as recently as Obama's unnecessary drone murders, but ranging from improper harms done to US troops, exposure to toxins, Abu Ghraib abuses of civil liberties, some of what's happened at Gitmo, etc. Each and every time we recognize a harm done, we should at the very least hold ourselves, collectively, responsible, and seek to be better. Accountability is a civic duty, regardless of political affiliation or philosophy. We should also be honest about necessary evils, not allow ourselves to be manipulated by bad faith actors, back up positions and words with actions and force, and hold ourselves to the highest possible standards. If we find ourselves continuously presented with no alternatives except between two evils, we should choose the lesser evil which allows us to preserve ourselves (otherwise, what are we even doing?)
The US body politic has allowed assumptions of good faith by our bureaucrats and military brass and politicians to fester into unimaginable corruption and vice, proving Eisenhower a prophet. We should simply be better - little things, important things, ground up discipline, principles, and a persisted social construct upon which to stably build a nation's strength is 100% necessary.
A lot of what Trump and Hegseth are doing pushes in that direction. Some aspirational, some performative, some well intentioned but wrong, but I think it's mostly in good faith, and I can get behind that.
I wish more on the left would at a bare minimum wish everyone to be responsible and to do well, for everyone to be happy, healthy, prosperous, and free. It has to be permitted to hope that whoever is in power achieves victories and success in those basic things, or we've lost the plot.