Bernie Sanders is trying to rebrand socialism in the U.S., but he'll have to overcome common fears about what the word means — fears the Trump campaign is watching and waiting to exploit.

Why it matters: Sanders may face a major challenge in convincing Americans in their 40s or older that there's a meaningful difference between what he supports, described as democratic socialism, and the authoritarian socialism that we've seen in regimes like Venezuela.

COLUMBIA, S.C. — Most Joe Biden admirers Axios interviewed in South Carolina, where he's vowed to win today's primary, said they're unfazed by his embarrassing losses in Iowa, New Hampshire and Nevada.

Why it matters: Biden has bet it all on South Carolina to position himself as the best alternative to Bernie Sanders — his "good buddy," he tells voters before skewering Sanders' record and ideas.

Former Vice President Joe Biden told CNN Friday morning that he had not been arrested during a 1970s trip to South Africa during which he tried to visit Nelson Mandela, despite recently claiming he had been.

Why it matters: Biden made the claim multiple times while campaigning in South Carolina, where he is trying to court a sizable base of black Democratic voters in this weekend's primary contest. The Washington Post and the New York Times questioned the credibility of the claims and could not find any official confirmation of the arrest.

Fracking is big business in some swing states, but several Democratic presidential candidates have pledged to end the controversial energy extraction process if elected. Dan and Axios' Ben Geman dig into the politics and practicality of a fracking ban.

• Go deeper: Sanders and Bloomberg break over fracking

Spending on the 2020 presidential primary has officially surpassed the $1 billion mark, with more than half of that total coming from billionaire Michael Bloomberg, according to data from Advertising Analytics.

Why it matters: It's the most money that has been spent this early on in an election cycle in U.S. history.

Former New York Mayor Michael Bloomberg apologized in a call with transgender leaders on Thursday for previously referring to transgender people as "it" after more than a week of silence on the issue, per NewNowNext.

Driving the news: BuzzFeed reported on the ex-mayor's 2019 remarks earlier this month, citing a recently uncovered video in which Bloomberg stated: "If your conversation during a presidential election is about some guy wearing a dress and whether he, she or it can go to the locker room with their daughter, that’s not a winning formula for most people."

Mike Bloomberg released new information on his heart health Thursday and called on his rival Bernie Sanders to do so as well.

Why it matters: The development, first reported by CNN, continues a public feud between the two candidates, both of whom are 78 years old. The move appears to be an attempt by Bloomberg to make Sanders' health a central issue in the Democratic contest.

Former President Obama's office is calling on South Carolina TV stations to stop running a misleading attack ad by a pro-Trump super PAC that uses Obama's voice out of context to make it appear as if he is criticizing Joe Biden and Democrats on race.

Why it matters: It's a rare intervention by Obama, whose former vice president is facing a critical primary in South Carolina on Saturday. Obama has said he has no plans to endorse in the Democratic field.

The Trump campaign is leaning into its effort to woo African American voters, opening "Black Voices for Trump" offices across six swing states, the campaign says.

Why it matters: "Woke" stickers, "Black Voices for Trump" T-shirts and other branded swag are part of this storefront approach as the campaign ramps up its efforts to erode Democrats' lock on this key demographic.

Former New York Mayor Mike Bloomberg is going after President Trump for his response to the novel coronavirus outbreak in a new ad set to air nationally on Thursday, his campaign announced Wednesday.

Why it matters: The 30-second spot claims the U.S. is "underprepared" for the crisis, while highlighting Bloomberg's response to the 9/11 attacks and health emergencies during his time as mayor. Bloomberg is the first candidate to air an ad about the coronavirus, per NBC's Josh Lederman.