I suspect they would not want to be put in the position of supporting a European nation against Russia.

Exactly, which is why the meeting was held. They do not want their commitment tested at this time, as it would potentially lead to high(er) volatility with uncertain odds of success.

In fact my reading of Trump is that warfare is not really his cup of tea, making Iran a big shock to me.

He got sold into it by Netanyahu and is now stuck in the quagmire we see before us. He thought we'd be in and out, "Mission Accomplished" banner unfurled in a few days. Bad news.

"Diplomacy is the art of saying 'Good Dog' until you make it to the rock."