In a Monday morning Tweet, Trump said Schultz “doesn’t have the ‘guts’ to run for President!” and took the opportunity to promote his own work as U.S. commander in chief.

“Watched him on @60Minutes last night and I agree with him that he is not the ‘smartest person.’ Besides, America already has that!,” Trump wrote. “I only hope that Starbucks is still paying me their rent in Trump Tower!”

On Sunday, Schultz said he might run for president as an independent candidate. He was equally critical of both the Democratic and Republican parties and lectured on Trump using social media as a bully pulpit.

“I think, like most people, I’ve become bored with President Trump and his tweets,” Schultz said.

In the same interview, Schultz said he has “a long history of recognizing, I’m not the smartest person in the room.” He explained, as CEO he surrounded himself with smarter people so he could understand situations before making decisions.

Schultz, who is worth an estimated $3.2 billion, according to Bloomberg, has been politically outspoken and a frequent critic of Trump’s presidency.

As a political candidate, however, Schultz could represent a threat to Trump. Schultz, just like Trump, can claim the mantle of political outsider, which is increasingly popular with voters. And he knows how to sway people’s opinions. After all, he is the man who largely convince a country to spend $4 or more on a cup of coffee.

Ironically, a Schultz run could lock in a second term for Trump, say top Democrats. His moderate leanings could split the party, they fear, as Republicans unite behind Trump.