President Trump Calls Koch Brothers a ‘Total Joke’ As They Attack His Trade Policies

President Donald Trump on Tuesday attacked the billionaire Koch brothers, calling the businessmen and longtime conservative activists a “total joke” and “two nice guys with bad ideas.”

“They want to protect their companies outside the U.S. from being taxed, I’m for American first and the American worker — a puppet for no one,” Trump tweeted.

Trump’s criticisms come a day after Charles Koch told reporters that Trump’s trade policies would be “disastrous.” Meanwhile, the powerful Koch network of political donors said it would not back a Republican candidate in North Dakota who they view as insufficiently critical of Trump and his economic decisions.

Charles and David Koch have poured millions of dollars into ads and advocacy over the years, typically for conservative candidates and causes. They backed Mitt Romney in 2012, but did not support either Trump nor his opponent, Hillary Clinton, in 2016. David has now retired from the group. But in a rare interview with reporters on the sidelines of donor conference Monday, Charles discussed his dismay over the Trump administration’s moves on trade, spending and immigration, including Trump’s use of protectionist economic policies, including tariffs.

“Any protectionism at any level, certainly at a national level, is very detrimental,” Charles Koch told reporters at the event in Colorado Springs, Colo. “There are scientific and historical reasons. I mean, every nation that has prospered is one that didn’t engage in trade wars.”

Charles Koch suggested that he would only back politicians who support a free trade, business-friendly agenda—even if that meant backing Democrats. That aligned with the announcement Monday by the Koch-backed group Americans for Prosperity that it would not back Republican Representative Kevin Cramer in North Dakota because of his support for a $1.3 trillion spending bill that increases funding for domestic and military programs, as well as his reticence in taking on the White House over tariffs.

“If this were 2016, we likely would have gone ahead and endorsed,” Americans for Prosperity President Tim Philips told backers Monday, according to CNN. “But we’re raising the bar.”

Trump’s policies on trade in particular have provoked ire among some Republicans, especially those in states most affected by retaliatory tariffs enacted by China, Canada, the European Union and beyond. The Trump administration announced last week a $12 billion spending plan to support farmers, particularly Midwestern soybean producers. On Monday, Freedom Partners, another Koch-backed organization, released an ad directly targeting farmers, asking them to reject Trump’s policies because farmers “want trade not aid.”

Disclosure: Time Inc., TIME’s parent company, was acquired by Meredith Corp. in a deal partially financed by Koch Equity Development, a subsidiary of Koch Industries Inc.