The United States would utterly destroy them and any other country (except mayyybe China) in an outright military battle. Like it wouldn't even be close.
We have 20 aircraft carriers here in America. No other country has more than one aircraft carrier. Our military dwarfs other militaries both technologically, financially, and in sheer power. Just spitballing but I bet we could probably reduce our military strength by 50% and still beat almost every country in the world.
However, the massive force equalizer is Russian nuclear weapons and I don't see Ukraine getting rid of any of those.
I learned something new today! Apparently Ukraine used to be the third largest nuclear power in the world, then handed them all back to Russia.
> The former Soviet Union had its nuclear program expanded to only four of its republics: Belarus, Kazakhstan, Russia, and Ukraine. After its dissolution in 1991, Ukraine became the third largest nuclear power in the world and held about one third of the former Soviet nuclear weapons, delivery system, and significant knowledge of its design and production.[2] Ukraine inherited about 130 UR-100N intercontinental ballistic missiles (ICBM) with six warheads each, 46 RT-23 Molodets ICBMs with ten warheads apiece, as well as 33 heavy bombers, totaling approximately 1,700 nuclear warheads remained on Ukrainian territory.
https://en.wikipedia.org/wiki/Ukraine_and_weapons_of_mass_de...
Ukraine is destroying Russian military equipment and killing its soldiers; I think that's a strategic win to weaken Russia. Plus the US frankly needed to claw back some of its reputation after Trump, so aligning against an invader helps that while avoiding outright war.