If Trump said that there would be quite a few people in Brussels in need of a change of clothes.
If Trump shut down trade and started pulling out our troops the Euro would drop like a stone. It would be worth 10 cents against the dollar in just a few days. Italy, Spain, Greece, France, Germany and more would declare they were no longer part of the EU.
It would be the near instantaneous end of the EU.
While the dissolution of the EU would be a good thing, such a rapid collapse has considerable peril.