Charles Koch over the weekend called Trump’s tariffs “unfair” to foreign countries and their workers.“This is ridiculous, we should just get rid of all barriers except on things that will hurt people,” Koch told the media during a donor summit in Colorado, according to ABC News. “It’s unfair to their people,” Koch added.

Trump slammed Charles Koch and his brother David on Tuesday after reports emerged that the network criticized Trump’s trade policies. “The globalist Koch Brothers, who have become a total joke in real Republican circles, are against Strong Borders and Powerful Trade,” Trump said in a series of tweets early Tuesday.