The issue is really that the US State Dept, DoD and CIA told the White House they could achieve a Russian defeat, and glorious Ukrainian victory for mere money and a few aged arms due to rotate out of US service.
They told the same story in all the European capitals.
They are deeply, deeply invested.
And completely full of bullshit.
There will be no direct NATO involvement.
How long can the Ukes hold out before defeat with too old arms delivered too late to really help?