President Donald Trump on Tuesday launched an attack on the Koch brothers, political megadonors with a history of supporting Republican and libertarian causes.

The Kochs have started speaking out against Trump, and they recently said they would consider donating to Democrats as well.

Trump bashed the brothers as having bad ideas and being "overrated."

President Donald Trump on Tuesday launched an attack on the Koch brothers — powerful political megadonors with a long history of supporting Republican and libertarian causes — after the billionaires spoke out against the Trump White House.

Charles Koch, who remains in business at Koch Industries after his brother David took a step back in June over health issues, recently distanced himself from Trump's policies and bashed his economics.

"The urge to protect ourselves from change has doomed many countries throughout history," Koch said in a video shown to a gathering of donors in Colorado Springs, Colorado, according to The Wall Street Journal.

"This protectionist mind-set has destroyed countless businesses."

That was not the first time the Koch network had sought to use its political influence to push back against Trump.

The Kochs offered millions in campaign funding to Republicans who voted against a Trump-backed healthcare bill last year, and they spoke out against Trump's "zero tolerance" immigration policy in which families that entered the country illegally were separated at the border.

But recently, Charles Koch opened up to the possibility of funding Democratic candidates in their efforts to take both chambers of Congress in November.

With months to go before a crucial Senate election in North Dakota, the Koch network has not offered any funds to the Republican candidate.

In the clearest sign of an about-face at the libertarian-leaning Koch network, the billionaires funded a study that found that a Medicare-for-all plan by Sen. Bernie Sanders of Vermont would save the US $2 trillion over a decade. Sanders thanked the Koch network by name.

Trump, on Tuesday, sounded off on the recent shift in the Republicans' base of power.

From Trump's Twitter:

"The globalist Koch Brothers, who have become a total joke in real Republican circles, are against Strong Borders and Powerful Trade. I never sought their support because I don't need their money or bad ideas. They love my Tax & Regulation Cuts, Judicial picks & more. I made them richer. Their network is highly overrated, I have beaten them at every turn. They want to protect their companies outside the U.S. from being taxed, I'm for America First & the American Worker - a puppet for no one. Two nice guys with bad ideas. Make America Great Again!"

Trump has consistently framed his policies as favoring workers, often citing economic growth and job numbers at near-record highs to bolster his case, though the vast majority of economists say his policies could lead to ruin for some sectors of the economy.

Against an overall trend of rising employment, some sectors of the economy have felt the heat of Trump's international trade disputes already.