Since Europe Won’t Step-Up to Shoulder Most of Ukraine War Burden Russia in Their Backyard Why Should the U. S.?

The economies of the EU nations combined roughly equal that of the U. S., so considering Russia is the supposed imminent threat to those nations of Europe because Russia is fighting in Ukraine (which is not a NATO member), right in Europe’s backyard, shouldn’t the EU be supplying 90% of the military support for the Ukraine War rather than the U. S. providing that percentage of the support?