The EU has a 10% tariff on US vehicles. The USA has a 2.5% tariff on European vehicles, except for the chicken tax The USA could simply match the EU's tariff and hurt the Germans.
But I would rather have an open system of positive mutual favoritism with a consistent set of tariffs for _everything_ rather than the faux free trade, rampant protectionism and piecemeal tariffs and subisidies we have now.