America is the only nation on that list that matters. Washington would be expected to do the heavy lifting in any war that includes Moscow, handle the nuclear exchange, conduct the air war, resupply the allied combatants, clear the seas, manage the ground campaign, and take the casualties. The UK and France would help out. Poland would contribute. Everyone else would offer advice and hope that Russia fired its weapons over them toward North America.
This should remind us that we are lucky (or blessed) President George W. Bush failed in his effort to add Kiev (and Georgia) to NATO. Had he succeeded Washington would have been obligated to come to Ukraine’s defense if it invoked Article 5 against Moscow. Backed by the United States, Kiev would have been much more likely to take a belligerent approach toward Russia. Poroshenko would have advanced his reelection prospects and possibly triggered the sort of war that only offers the possibility of reclaiming Crimea.
While alliances deter, they also ensnare. If war breaks out, then Washington is automatically involved. And war becomes more likely when governments believe they can borrow the U.S. armed forces for their own purposes, which makes them more reckless.