The general public is hard-pressed to support basic research with taxes, but they do support unlimited defense funding. This is one hack that the US system uses to do basic research under the umbrella of defense.

This is anecdotal, but I've not run into a single real life American who hasn't agreed with the general premise that we spend too much money on "the military industrial complex". Even the hawkish folks agree with this notion to some extent, usually arguing that specific projects are a waste of money and that's where the cuts should come from.

Cynically, I think our congresspeople don't actually take our feedback about the budget into account. They'll talk a big game about wasteful spending and the need to reduce deficits but the pork never stops flowing.

Folks can say whatever they want, but the votes show that "no one ever got fired for increasing defense spending", while the opposite isn't true.

Because defense spending funds science research. See DARPA.

Really good introduction to it all https://www.amazon.com/gp/product/B07BLKXV68

But so does science research spending. Point seems to be why not let it follow directions independent of military utility.

Better science and tech than the other guy gives you a military advantage. Thus some fraction of your science funding is effectively military funding, and some fraction of your military funding is well spent on science.

Also, more science projects lead to more experienced scientists and engineers, which leads to a stronger pool for the defense industry.