European economy would implode without trading with US. The biggest economy in Europe, Germany; exports cars, pharmaceuticals and other high end machinery to US and the whole middle class in Germany relies on the jobs from those exports oriented companies
Cars are largely not exported to the US from Germany, but built in US factories. German car companies have factories all over the world.
You talk about Europe then only give Germany examples ..? Is that a German only problem ?
To be fair, it would be a bigger issue for the US. No country is more economically dependant on the rest of the world than the US. The US is living on the USD, and if others stop using it the US would have to do extreme cuts on everything.