PHILADELPHIA (CBS) – Former Pennsylvania Governor Ed Rendell addressed Vermont Senator Bernie Sanders formally endorsing Hillary Clinton for President, saying he thinks the overwhelming majority of Sanders primary supporters will turn out for the former Secretary of State.

Rendell told Rich Zeoli on Talk Radio 1210 WPHT to ignore current polls showing some resistance to Clinton from fans of her main primary challenger.

“The latest national polls showed about 30 percent of the Sanders supporters said they were not ready to say they were going to vote for Secretary Clinton. That sounds like a lot, but you have to consider when Secretary Clinton pulled out and endorsed President Obama, about 40 percent of her supporters said they would never vote for President Obama. On election day in November, about 95 percent of the people who voted for Hillary Clinton in the primaries voted for Barack Obama.”

He pointed out that much of Bernie’s support comes from outside the typical Democratic voter base.

“There are some people in the Sanders group who I think are unpersuadable. They’re people that were never Democrats. Many of them had never registered before. They’re independents. They’re free thinkers for different reasons. Some of them will vote for Jill Stein. Some of them will vote for Gary Johnson. Some of them just won’t vote for President. The question is, what percentage of the Sanders vote will vote for Hillary Clinton? If it’s anything over 80 or 85, I think she’s in pretty good shape.”

Ultimately, Rendell thinks Sanders will deliver the majority of his voters to Clinton.

“My guess, if I had to guess, would be in the high 80’s or somewhere around 90.”