Mayor de Blasio is in Puerto Rico today. The visit follows his trip to New Hampshire yesterday.

He was one of 19 Democratic hopefuls making their pitch to voters at a party convention there.

De Blasio touted his record running the city, turning progressive ideas into policy, and suggested another idea needed for the future—a robot tax.

"A plan to stop the tax breaks that are speeding up automation and taking away the jobs of millions of American workers,” de Blasio said to the crowd at the convention. “We have to be on the side of those workers, and while we're at it, every company that puts a worker out of their job should pay a robot tax."

De Blasio did not qualify for this week's debate in Houston. He said if he does not meet the requirements for the one in October, he'll consider dropping out of the presidential race.