(Image Credit: Carolyn Kaster/AP Photo)

Chicago Mayor Rahm Emanuel said it was "ridiculous" for Newt Gingrich to say that having former President Clinton speak tonight at the Democratic National Convention in Charlotte, N.C., was an "enormous risk" that would remind voters of how "pathetically bad Obama has been."

"That is ridiculous," Emanuel said today on "Good Morning America" of the former House speaker's comments.

"A former president who is very popular who can explain about the policies and the parallel tracks the two presidents have had in the sense of investing in education, investing in research and development, alternative energy and green energy and a responsible way of balancing the budget. I think he can do nothing but help and the notion that Newt is going to give our party strategic advice, no thank you."

Emanuel - a veteran of the both the Clinton and Obama administrations who is known for his sharp tongue - also took at shot at the GOP presidential ticket.

"Let me say this, my only advice to them, not that they would take it is I would not have Paul Ryan's fact-checker looking over Mitt Romney's tax returns," Emanuel said, referencing Romney's unwillingness to release more than two years of his tax returns and certain aspects of Ryan's speech at the Republican National Convention last week that some found misleading.

I also asked the Chicago mayor about a new ABC News-Washington Post poll that found that 47 percent of registered voters see Obama favorably overall, down 7 percentage points from his recent peak in April, while 49 percent rate him unfavorably. Emanuel did not express worry, but did say that the president needed to lay out his vision for a second term in the White House.

"There's no doubt that the president needs to talk about his vision for a second term and what it would mean for America. That's a requirement. I wouldn't call it a State of Union but I would call it about a clear choice in the direction he wants to take the country. He owes the country because if he gets elected, that kind of clarity," he said. "Clear policy choices, clear implications for the American people, different directions and this is a choice and I think that's what it's going to take and to finish that conversation the president will lay out his vision, not just for the next four years but the consequence for America going forward into the future."

Emanuel, citing his Jewish heritage, also called Republican attacks on Democrats' removing language from their party platform calling Jerusalem the capital of Israel a "red herring."

"As a person who has been to Jerusalem 20-plus times in his life, whose son just a couple of years ago had his bar mitzvah at the wall, this is a red herring, if I've ever seen one," he said.

Like "This Week" on Facebook here. You can also follow the show on Twitter here.

Get more pure politics at ABCNews.com/Politics and a lighter take on the news at OTUSNews.com .