(CNN)Hillary Clinton offered Bernie Sanders a backhanded compliment for coming around on a gun control issue, while Sanders expressed his disappointment that Clinton's daughter had been used to attack his health care plan. And Donald Trump weighed in on everything from Marco Rubio's citizenship to his own relationship with a higher power.
Best of 'State of the Union': Trump, Clinton and Sanders
They shared it all with CNN's Jake Tapper on "State of the Union," only hours ahead of the fourth Democratic debate, set for Sunday night in South Carolina, and just a little more than two weeks before Iowans head to the caucuses for the first vote of this 2016 nominating contest.
Here is the best of the best from this Sunday's show:
(On Saturday, Sanders announced he would support legislation to roll back 2005 law granting firearm manufacturers legal immunity, a bill he supported a decade ago. Clinton has repeatedly criticized his support of it.)
"One of my biggest differences has been on guns, and I'm very pleased that he flip-flopped on the immunity legislation. Now I hope he will flip-flop on what we call the 'Charleston loophole' and join legislation to close that," Clinton said.
"I didn't use her; she answered a question and she gave a factual answer," Clinton said.
"I'm just too busy campaigning," she said.
"No," she said simply, when asked if she had been interviewed by the FBI.
"I was a little disappointed that what Chelsea said was just not accurate," he said of Chelsea Clintons's attacks on his health care plan.
"Well, if you consider a Medicare premium as a tax, you know, that's true ... But, at the end of the day, the middle-class family, getting rid of all private health insurance premiums will save thousands of dollars a year in their health care costs," he said.
"What I said, Jake, is that there were provisions in that legislation ending armor-piercing ammunition, making sure that we had safety locks for kids in that bill. That made sense to me," Sanders said.
"I have a very good relationship with god, a great relationship with evangelical (Christian voters)," he said.
"I would have not done it because it's confusing. Some people believe me when I said -- I mean, I swear to you, that's true. I had no idea ... I swear to you," Trump said.
"I don't know yet. I haven't thought of it. I'm thinking about this one," he said.
"You need it because I think PACs are a horrible thing," he said.
"Ted Cruz, he's got a lot of people putting big money in, probably maybe Goldman Sachs, we'll have to ask them. I mean, they have loaned him a million dollars. So, they certainly have control over him," Trump said.
(Trump has said Cruz will face legal scrutiny over whether he is a "natural born citizen" as prescribed by the Constitution to serve as president, because he was born in Canada. Cruz is an American citizen because his mother is American.)
"You can't have a cloud. You can't pick a candidate that may have a 5%, 10%, 20% chance. By the way, since that happened, there have been lawsuits filed," Trump said. "Now, he's got a problem. He was born in Canada. He was a Canadian citizen until 15 months ago, I mean, if you can believe that."
"It's a very, very different thing because he was born here. He was born on the land. Ted was not born on the land."