the septics won't arm or mobilise for Ukraine in the way any side of this debate (either pro or anti) conceives it so it's a bit of a moot point tbh. People who parrot out this line tend to wish that policy makers can be won to argument through intellectual reasoning, and that's just not how capital exerts its impersonal domination. Already we can see the US political class doing everything to avoid netanyahu dragging them into confrontation with Iran, because the longer this war continues, the more untenable the US's position becomes as Israel self-destructs. I don't think the US wants to see a russian defeat in Ukraine because it relies on its mediating power in the Middle East and the baltic states. If Trump is going to do anything, it would be an attempt to withdraw from or dissolve NATO, which would signal American independence from Europe, a backwater in terms of global geo-politics.
I mean I'm not on the Russian aggressor side here but we have to be realistic. This argument for American exceptionalism was bankrupted in Iraq and Syria, why would it be successful now?