To paraphrase Hanlon's razor "Don't confuse reluctance with incompetence". The US is a rat's nest of different interests; it is too internally divided to fix hard problems. There are always wealthy political donors who control enough politicians to prevent a good solution. At this point, the US can only put lipstick on its incompetence. I do feel sorry for Ukraine but the GOP represents 40+% of the US electorate and they are now a cult rooted in disinformation (and supported by Russia). A nation this divided can't save itself; how can it save anyone else?
The funny thing about the America-divided narrative is that the majority of liberal-leaning American opiners fall back on that same explanation (and then sprinkle on some paranoia about the vast reach of Russian disinformation for good measure). Maybe a rat’s nest of different interests but still suprisingly united ideologically.
You posit that "the majority of liberals-leaning American"s hold the same beliefs in the "America-divided narrative" and yet conclude that everyone is "surprisingly united ideologically". That seems like a contradiction but it's possible we just disagree on what is ideologically important. For example, I think it is important that 74m Trump supporters think Trump is honest and an equal number of Trump haters think he is dishonest.
How do you think liberals-leaning and conservative-leaning Americans are united ideologically?