President Donald Trump on Thursday threatened to impose a massive tariff on European alcohol in response to the European Union’s retaliation against his steel and aluminum tariffs – a tit-for-tat escalation of a trade war that could easily get out of hand.

President Trump on Thursday threatened to impose tariffs on wines, Champagnes and other alcoholic products imported to the U.S. from France and other European countries in response to raised tariffs the European Union placed on American whiskey.

Trump said he would impose the tariff if the European Union continues with its plan to impose a 50% tariff on whiskey beginning in April.