If Europe was seeing 4M arrivals in Italy/Greece, meanwhile Mexico was invading Colombia, I think Europe would focus on the arrivals, not something happening halfway round the world, and in an area we regard as USA's backyard.
And its an election year, so yeah, 'domestic' is where its at. Yanks are unlikely to decide who to vote for, based on who will kill more russians in Ukraine.
And Germany just voted again not to supply Taurus. UK and Europe need to take the lead, not keep asking USA to do it. We have 2 nuclear powers, 3 aircraft carriers, 8 nuke missile subs, etc etc. And we have a lot of money - which becomes the same argument as USA, no-one is sending trucks of cash to Ukraine, its being donated mostly to be spent in our countries, on weapons for ukraine, etc.
That said, its still a massive and cheap way of winning what remains of the cold war, or improving our position for the next war, without losing our own people, for all of us inc USA.