Story highlights Grover Norquist's Taxpayer Protection Pledge is a promise by candidates not to vote for a tax increase

The Americans for Tax Reform President said he's yet to get the Republican presidential nominee to sign it

Party People is a new podcast from CNN where a pair of conservative CNN contributors talk to influential voices about the future of conservatism and the Republican party.

(CNN) With less than a month until election day, Americans for Tax Reform President Grover Norquist said Republican presidential nominee Donald Trump has yet to sign on to his signature pledge to never raise taxes.

"If asked, the answer is Trump has not made the commitment in writing," Norquist told CNN's "Party People" podcast hosts Kevin Madden and Mary Katherine Ham in a recent conversation.

Norquist continued, "He has to his credit publicly said to Time magazine and out loud, 'I will never support a tax increase' and his tax plan is fine."

Madden followed up, "He's also publicly said things and then publicly said he did not say those things."

"That is why -- and not just for Trump -- that is why we want it in writing for everyone," Norquist said. "So, I'm not going off his verbal statement. We are waiting for the pledge. I do expect that we will eventually get it."