"Honestly, until this phone call, I didn't know it was a problem," he said when he called in to the Today show Tuesday morning. "I'm very surprised to hear it."
With just one week to go until March 15th – when GOP primaries in Florida, Ohio, Illinois, and elsewhere will help determine the Republican nominee for president – the party front-runner has been calling on attendees of his rallies to raise their right hands and take a loyalty oath to vote for him.
"I mean, they're having such a great time," Trump said of attendees he asked to take the pledge at a Mississippi rally on Monday. "They're massive crowds. I get, you know, by far, the biggest crowds and we're having a good time."
"Sometimes we'll do it for fun, and they'll start screaming at me, 'Do the swear-in! Do the swear-in!' If it's offensive, if there's anything wrong with it, I wouldn't do it," he said on the Today show.
Trump first asked supporters to "do a pledge" during a rally in Orlando, Florida, on Saturday, where he raised his right hand and told the crowd, "Everybody – who likes me in this room? Okay, I've never done this before, can I have a pledge – a swearing – raise your right hand. I do solemnly swear … that I, no matter how I feel, no matter what the conditions, if there's hurricanes or whatever … will vote for you on or before the 12th … for Donald J. Trump for president. Thank you. Now I know. Don't forget you all raised your hand. You swore. Bad things happen if you don't live up to what you just did. Naw, I really appreciate it."
Trump asked attendees at a rally in North Carolina on Monday to raise their right hands for a similar pledge. He also had plainclothes private intelligence officers on hand to search for protestors, as well as extended barriers to cordon off the media and prevent them from entering the crowd to document protests and scuffles.
"These new tactics represent refinements by Trump and his staff in their quest to control the atmosphere and message of his often unruly rallies," writes Politico's Ben Schreckinger.
Comedian Louis C.K. and conservative radio host Glenn Beck are among those who compared Trump to Nazi leader Adolf Hitler over the weekend. "We all look at Adolf Hitler in 1940. We should look at Adolf Hitler in 1929," Beck said on ABC's This Week on Sunday. "Donald Trump is a dangerous man with the things that he has been saying."
And Louis C.K. warned fans in an email, "We are being Germany in the '30s. Do you think they saw the s--- coming? Hitler was just some hilarious and refreshing dude with a weird comb over who would say anything at all."
Some of the harshest criticism came from Holocaust survivor Abraham Foxman, the former director of the Anti-Defamation League, who called Trump's loyalty pledge and salute "offensive, obnoxious and disgusting."
"As a Jew who survived the Holocaust, to see an audience of thousands of people raising their hands in what looks like the 'Heil Hitler' salute is about as offensive, obnoxious and disgusting as anything I thought I would ever witness in the United States of America," Foxman told the Times of Israel.
"It is a fascist gesture. He is smart enough – he always tells us how smart he is – to know the images that this evokes. Instead of asking his audience to pledge allegiance to the United States of America, which in itself would be a little bizarre, he's asking them to swear allegiance to him."
"We've seen this sort of thing at rallies of neo-Nazis," he added of the raised-arm salute that was once a show of obedience to Hitler. "We've seen it at rallies of white supremacists. But to see it at a rally for a legitimate candidate for the presidency of the United States is outrageous."
Trump's loyal following is helping him maintain his advantage in the 2016 race, but a new Washington Post-ABC News national poll shows that his lead over rival Ted Cruz has narrowed from 16 points in January to nine on Tuesday. Trump still has the support of 34 percent of registered Republicans and Republican-leaning independents, while the Texas senator has 25 percent support.
On Tuesday, Republicans will vote in Michigan, Mississippi, Idaho and Hawaii, and Trump will see if his supporters stand by their pledges to him. Asked on the Today show if he would stop doing the oath, considering the Nazi comparisons, Trump replied, "Well, I'll certainly look into it. I mean, I'd like to find out that that's true, but I'll certainly look into it because I don't want to offend anybody. But I can tell you that it's been amazingly received."
Weighing in on the "is-Trump-really-a-Hitler-style-fascist" question, Jane Eisner, editor of the Jewish media outlet the Forward, quoted Holocaust historian Deborah Lipstadt:
"Some people didn't approve of Hitler's anti-Semitism, but they went along with it because he was going to make Germany great again."