Democratic vice presidential nominee Tim Kaine said he doesn’t think people should trust assurances from GOP running mates Donald Trump and Mike Pence that they don’t want to cut Social Security.

“Donald Trump wrote a book and he said Social Security is a Ponzi scheme and privatization would be good for all of us,” Kaine said during Tuesday’s vice presidential debate in Farmville, Virginia, accurately describing passages from a book Trump wrote in 2000.

“When Congressman Pence was in Congress, he was the chief cheerleader for the privatization of Social Security,” Kaine continued, referring to a push during the George W. Bush administration to invest Social Security payroll taxes in the stock market instead of government bonds. The effort, which Pence supported as a congressman, fizzled in 2005.

Despite this past support for privatization, the Trump campaign has said it doesn’t want to touch Social Security, and that instead of cutting benefits or raising taxes, Trump would fix the retirement program’s long-term financing problems simply by making America’s economy great again.

Pence on Tuesday objected to Kaine describing his past position, reaching for an old debate chestnut.

“There they go again,” Pence said, to some laughter from the debate audience. “All Donald Trump and I have said about Social Security is we’re going to meet our obligations to our seniors.”

Kaine explained that he and Clinton supported improving Social Security’s finances partly by increasing the amount of wages subject to Social Security taxes. Currently, only the first $118,500 of wages is subject to the tax.

“We are going to stand up against that push to privatize Social Security and look for ways to keep it solvent going forward, focusing on the payroll tax,” Kaine said.