President Donald Trump will meet Monday with billionaire philanthropist Bill Gates, who has been sharply critical of Trump's plan to slash funding for foreign aid programs.

Last week Gates, the founder of Microsoft (MSFT), wrote a blog post entitled "How foreign aid helps Americans."

Spending money on other countries makes Americans safer, Gates argued. U.S aide can help stabilize volatile and vulnerable parts of the world, combat the outbreaks of epidemics, and strengthen the market for U.S. goods.

"[A]id delivers phenomenal benefits, and for a bargain," Gates wrote. "It represents less than 1% of the federal budget, not even a penny out of every dollar."

The Trump budget proposal proposes deep cuts in foreign aid. "It is time to prioritize the security and well-being of Americans, and to ask the rest of the world to step up and pay its fair share," the administration wrote.

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Gates also comes down on the other side of Trump on immigration and climate change.

He is a founding member of FWD.us, a group of mostly tech executives urging immigration reform to allow a path to citizenship for more immigrants.

And in December Gates pledged to invest $1 billion to back "radical clean energy ideas," arguing that rich countries need to be net zero emitters of carbon dioxide by 2050. The Trump administration has been critical of calls to combat global warming. Its proposed budget for the EPA would drop research into climate change.

This is not the first time since the election that Gates has met with Trump. He visited with Trump at Trump Tower in December, the day after he announced clean energy investment plans.

Gates is set to meet with Trump at 11 a.m. at a White House meeting closed to the press.