The billionaire received a 61 percent favorability rating in Iowa.
“That is a legitimate issue for us to look at,” Scott Walker said.
Biden is too much of an insider to challenge Sanders, according to New Gingrich.
“We have to continue to rebuild the coast," Mitch Landrieu said.
The Louisiana governor said the last 10 years have shown Americans' resilience.
Michael Needham said outsiders are in touch with "conservative populist primary voters.”
“The worst part about this is her arrogance,” Christie said.
"“Donald Trump can say whatever he wants to say about Jeb. But saying that he’s low-energy is wrong...
Fiorina was fired as Hewlett-Packard's chief executive a decade ago.
“They didn’t work in the past,” Walker said of attacks on his record.
Brown said if he were Biden, he would give "very serious consideration" to running.
“You’ve got to think about this in plain language,” Howard Dean said.
“We all know that Hillary Clinton is held to a different standard,” Ellen Tauscher said.
"I think all things are possible," he said, however.
Trump said agents are "not allowed" to do their jobs.
Ben Carson did say that drones could be used to destroy smugglers' caves without casualties.
"As usual, the cover-up is worse than the crime," she said.
Discussions turned to Republican and Democratic candidates.
"We could be leading a coalition of Arab allies to defeat ISIS,” she said.
“I think we can change that,” Sanders said.
“There’s a lot of partisan stuff going on that’s not fair" to Clinton, Klobuchar said.
Bush said Trump's immigration proposals would be too costly and impractical.
“When people see the benefits of our reforms ... I think our numbers will go up," Walker said.
“I'm talking about enforcing the laws of this country," Walker said.
"It just seems to be one scandal after another,” he said.
“I do not accept the fact that I have been weak on this issue," he said.
"I have let the leadership of the Democrats know," Sanders said.
Discussions also turned to a possible Biden presidential run.
"We need to have start having debates about the issues," he said.
“Any change in birthright citizenship ... will take many, many years,” he said.
"I just think it’s a very complicated problem," Christie said.
“I turned down $5 million last week from a very important lobbyist," he said.
“He’s a force to be reckoned with,” Huckabee said.
“There’s tremendous divisions throughout the state,” Trump said.
“The question is what she knew about what was on those emails," Michael Mukasey said.
"I will use all of my energy, as our nominee, to defeat her," she added.
“I think she may not be able to run, to be honest," he said.
O’Malley said the “electorate actually looks at candidates in a very holistic way.”
“If I’m commander in chief, we’re going after these guys," he said.