It’s a good thing former Chicago Public Schools CEO Paul Vallas has developed a “thick hide” in over 40 years in public service.

He needs it—and a flak jacket—with all of the political heat he is getting in the nine-way race for mayor of Chicago.

“I’m the frontrunner. That’s the reason. They know I’ve got momentum. They know I’m rising in the polls. They know that I’m a threat. And this time, they’re gonna try to attack me personally as opposed to challenge me on the issues,” Vallas said Friday.