“They are a NATO problem, and the U.S. is part of NATO.”
Great. We could provide logistical support, but no troops on the ground. Trump will not be sucked into WW3. Europe is strong enough to take on Russia without the US military.
If they all go nuclear and nuclear war becomes the final answer that replaces conventional war, then it will be easier to sell the U.S. conventual capabilities pulling out of NATO as the primary force keeping Russia from devouring Europe again.