Cruz was conferred American citizenship at birth because his mother is an American citizen, and legal experts have largely agreed that would qualify him for natural-born citizenship. The Texas Republican also had Canadian citizenship until he renounced it in 2014.
"He was born in Canada. He was a Canadian citizen until 15 months ago, if you can believe that," Trump said.
"He says he didn't know," Tapper replied.
"He didn't know. Well, he didn't know about his financial papers either. You know, how are you going to be president if you didn't know about a million dollar loan from Goldman Sachs," Trump asked, referring to a controversy that surfaced earlier this week over Cruz's 2012 Senate bid. "And you said it's something you don't know about. Now he doesn't know that he was a Canadian citizen? I mean that's in a way maybe worse than all the other things we're talking about."
A lawsuit was filed this week
questioning Cruz's eligibility for the presidency, as Trump predicted.
"There have been lawsuits filed. And I said lawsuits are going to be filed," he said. "The Democrats are going to file lawsuits. They filed lawsuits. Now, he's got a problem."
Trump also hammered Cruz over his criticism of "New York values," which the Texas senator said referred to the Empire State's support of abortion rights, same-sex marriage and a focus on money and greed. Trump called those remarks "very, very insulting."
"I immediately thought of the World Trade Center, and the bravery of New Yorkers and the genius of New Yorkers to be able to take that whole section and rebuild after the tragedy," he said.
Asked if Cruz was making a subtle ethnic dig with his "New York values" comment, Trump said he didn't know, adding, "probably you would have to ask him."
But, Trump said, "I thought it was disgraceful that he brought that up ... I think he came across badly. Some people gave him pretty good reviews on the debate. I think he came across as very strident and not a nice person, and people don't like that."
Trump said the "only place (Cruz) is doing fairly well is in Iowa."
"I you look at these other places, he's not doing well, and certainly not doing well nationally," Trump added.
Still, he doesn't want to take any chances, which is why he's been spending on ads recently.
"I'm going to start spending money for two reasons. Number one, I feel guilty because I'm $35 million under budget," he said. "Number two, I don't want to take a chance."
Trump pointed out that spending millions has not helped former Florida Jeb Bush emerge as a leading candidate.
"Jeb is spending so much money. Think of it, he spent $69 million, I spent nothing. He's at the bottom of the pack, I'm at the top of the pack," he said.
He then attacked former presidential candidate Lindsey Graham for endorsing Bush.
"I think it's incredible. First of all, Lindsey Graham got out with zero. He had zero. He had nothing. That's number one, so he's not gonna get any voters and I think it's a very bad thing for Lindsay Graham," Trump said.
On Trump's 'deportation force'
Tapper asked Trump about his proposal to create a "deportation force"
to remove the estimated 11 million undocumented immigrants living in the U.S. In the past, Trump has cited the efforts of President Dwight Eisenhower to remove undocumented immigrants as part of "Operation Wetback"
during the 1950s.
"A lot of people think that was a shameful chapter in American history, though," Tapper said.
"Well, some people do, and some people think it was a very effective chapter, and what happened was when they removed some, meaning brought them back, when they brought them back, they removed some, everybody else left," Trump said. "And it was very successful, everyone said. So I mean, that's the way it is. Look, we either have a country, or we don't. If we don't have strong borders, we have a problem."
Campaign finance reform
Trump said the American political process is in need of campaign finance reform, adding that he -- a candidate who has repeatedly touted his decision to self-fund his campaign as a selling point for his candidacy -- hasn't decided if he would accept public financing for the general election.
"I don't know yet. I haven't thought of it. I am thinking about this one," he said.
Trump also said Cruz
and other candidates are more likely to do the bidding of their donors if elected opposed to looking out for the best interest of the country.
"That's the way it is. Somebody gives them money. Not anything wrong, just psychologically, when they go to that person, they're going to do that," he said. "They owe them, and by the way, they may therefore vote negatively towards the country. That's not gonna happen with me."
The American political process is in need of campaign finance reform, Trump said.
"Well I think you need it, because I think PACs are a horrible thing," he said. "First of all everybody is dealing with their PAC. You know, it's supposed to be like this secret thing -- they're all dealing."
Trump says he wasn't mocking reporter with disability
Trump was previously criticized for appearing to mock Serge Kovaleski, a New York Times reporter with arthrogryposis, a chronic condition which limits the movement of his arms.
At a South Carolina rally in November, Trump waved his arms in an awkward manner while discussing a comment made by Kovaleski. But Trump said he wasn't mocking him.
"If you could go back and do it again, would you do it differently?" Tapper asked.
"Yes, I would. But let me just tell you something. I had no idea what this reporter looked like or that he had difficulty," Trump said.
Trump told Tapper he would never mock a person with a disability.
"I was not imitating. I would never -- who would ever do that? If somebody had a disability, who would mock a disability? I would never. I'm a smart person ... Who would ever mock somebody, especially if you're running for office?" Trump said.
"I would have not done it, because it's confusing," he added. "Some people believe me when I say it, I mean, I swear to you, that's true. I had no idea."
Trump and God
Trump said he is doing so well with evangelicals
because he has a "very great relationship with God."
"One of the potential attack lines has to do with an answer you gave to Frank Luntz months ago
when you said that you've never asked God for forgiveness. Do you regret making that remark?" Tapper asked.
"No, I have a great relationship with God. I have a great relationship with evangelicals," he said.
Trump said he doesn't ask for forgiveness because he doesn't do a lot of bad things.
"I don't like to have to ask for forgiveness. And I am good, I don't do a lot of things that are bad, I try and do nothing that's bad. I live a very different life than probably a lot of people would think," Trump said.
Haley criticism was an 'honor'
Tapper asked Trump how it felt to be implicitly criticized by South Carolina Gov. Nikki Haley in her Republican response to President Barack Obama's State of the Union address last week.
"It was my great honor because I'm angry and they both said I was angry. And I get along very well with Nikki, and you know, Nikki said we're friends and we are friends. I supported her, but I am angry," Trump said. "And when she said there's an anger that we shouldn't have, I said, well, I disagree with one thing. There's an anger that we should have. Our country is going to hell."