Bernie Sanders and Hillary Clinton. AP Photo/David Goldman Hillary Clinton's campaign has brought out the firepower quickly after her crushing loss to Sen. Bernie Sanders (I-Vermont) on Tuesday night in the New Hampshire Democratic primary.

"When you match up the record of Hillary Clinton with the record of Bernie Sanders, it simply is no comparison," Rep. Hakeem Jeffries (D-New York) said Wednesday in a campaign conference call.

"Hillary Clinton has been at the dance from the very beginning of her career. [Sanders] is a new arrival at the dance. And for many of us, it simply lends no credibility for some of the things that are now being said at the twilight of his political career."

This is a preview of what's to come ahead of the next two nominating contests in the Democratic primary process: the Nevada caucuses on February 20 and the South Carolina primary on February 27. The two will debate Thursday night at 9 p.m. ET on PBS.

In an increasingly heated primary battle, Sanders is attempting to ride his momentum to cut into Clinton's "firewall" — her perceived advantage with those states' more diverse electorates. Meanwhile, Clinton and her campaign have rolled out pillars of that strength over the past two days — particularly in South Carolina, where winning among African-American voters will be key to capturing victory in the state.

The difference between the electorates of Iowa and New Hampshire and that of South Carolina could hardly be more stark. More than 92% of Iowans and 94% of New Hampshirites are white, according to the US Census Bureau. South Carolina, by contrast, has a black population that is greater than 25%, and a majority of South Carolina Democrats are black.

In the Palmetto State, 81% of African-American voters consider themselves Democrats, according to a January CBS/YouGov poll. That compares with just 23% of white voters in the state. Among black Democrats in the state, Clinton led Sanders by 54 points in the survey. Sanders was ahead with white voters by 22 points, but he was trailing Clinton overall 60% to 38%.

"She's definitely got some sister in her," Bernice Scott, a Clinton supporter in South Carolina, told The New York Times in reference to how impressed she was of Clinton's demeanor in front of Congress when questioned during the most recent hearing on the 2012 terrorist attack in Benghazi.

Scott added: "She didn't back down."

That January poll, however, was taken before Sanders' strong showing in Iowa earlier this month and his large victory in New Hampshire on Tuesday, which could have more voters considering Sanders as a more serious candidate. The Clinton campaign is taking steps to ensure its candidate does not lose her edge.

In 2008, Clinton lost the black vote in South Carolina to then-Sen. Barack Obama by nearly 60 points, losing overall in the state 55.4% to 26.5%. This time around, she has the Congressional Black Caucus publicly endorsing her.

The caucus' political action committee announced its support of Clinton on Thursday. The group also said it would send lawmakers to South Carolina and other coming states.

"It's one thing to endorse and do nothing. It's another thing to endorse and to go to work," Rep. Gregory Meeks (D-New York) told The Washington Post, adding that lawmakers in the caucus were "people that can actually testify [to] the work that Hillary Clinton has done."

Hillary Clinton. AP Photo/David Goldman In the Clinton campaign conference call, several black leaders expressed support for the former secretary of state while saying Sanders had been "missing in action" when it came to fighting for issues of importance to black voters.

Jeffries said Clinton's strong stance and history on gun control was a major reason he thought she was the right choice. Clinton has made a habit of targeting Sanders' more conservative history on guns.

"He's done the bidding of the NRA," he said of Sanders, referring to the National Rifle Association.

"For someone like myself, who represents neighborhoods of East New York and deals with the reality of young, African-American men being killed, every year, by the hundreds, throughout the city and beyond in terms of gun violence, I want someone who as commander-in-chief I can be confident will step in and be prepared to deal with this important issue for the African-American community," he added.

South Carolina House Minority Leader Todd Rutherford (D) cited Clinton's focus on criminal-justice reform and her support of the Affordable Care Act as reasons he was supporting Clinton. He added a criticism that while Sanders has a criminal-justice platform now, he voted for the 1994 crime bill that disproportionately hurt black Americans.

That controversial bill was championed by Clinton's husband, former US President Bill Clinton, and Hillary Clinton supported it at the time.

When asked about Hillary Clinton's statement from that time — when she said young black offenders were "often the kinds of kids that are called 'super-predators'" — Jeffries said he was "not intimately familiar with" the statement.

"I'm confident, based on the totality of her record, that she is genuine and authentic of her championing of issues," he said. "Her track record, her experience, all convince me that she's the best candidate to build upon the record of President Obama to take things forward."

Indeed, Clinton has also seen increased scrutiny over her past support for policies that critics say disaffected African-Americans.

Michelle Alexander, an Ohio State University professor and author of "The New Jim Crow: Mass Incarceration in the Age of Colorblindness" in 2010, wrote in The Nation that Clinton did not deserve the black vote, mainly because of her support of that controversial crime bill.

Sanders with Rev. Al Sharpton. AP Photo/Richard Drew "It seems we're eager to get played. Again," she said, referring to black support for Clinton's husband, who at one time was dubbed "the first black president."

Alexander said a "love affair" between black Americans and the Clintons seemed strange, considering the former president's stance on crime that Alexander said ultimately hurt many African-Americans. Moreover, Alexander wrote, President Clinton's economic policies didn't help black Americans, either.

She added that the former secretary of state shouldn't get a free pass, since she was not "picking out china while she was first lady."

"She bravely broke the mold and redefined that job in ways no woman ever had before," Alexander wrote. "She not only campaigned for Bill; she also wielded power and significant influence once he was elected, lobbying for legislation and other measures. That record, and her statements from that era, should be scrutinized."

Bill Clinton's 1994 crime bill "created dozens of new federal capital crimes, mandated life sentences for some three-time offenders, and authorized more than $16 billion for state prison grants and the expansion of police forces," she wrote, adding that Bill Clinton contributed to mass incarceration more than any other president.

Rutherford said Hillary Clinton had since acknowledged that the bill had a disproportionate racial impact, while he added "we have yet to receive an apology from Sen. Sanders."

Sanders has started to receive some critical endorsements from leaders in the black community. On Wednesday, acclaimed author Ta-Nehisi Coates said he was supporting the Vermont senator.

"I have tried to avoid this question, but, yes, I will be voting for Sen. Sanders," he told Democracy Now. "I try to avoid that, because I want to write as a journalist — do you know what I mean? — and separate that from my role as, I don't know, a private citizen. But I don't think much is accomplished by ducking the question. Yes, I will vote for Sen. Sanders. My son influenced me."

The same day, Sanders met in New York City with prominent black activist Rev. Al Sharpton, who has not yet made an endorsement in the presidential race.

And even in South Carolina, some Clinton supporters are beginning to stray over to the Sanders camp.

State Rep. Justin Bamberg (D), who recently switched his support from Clinton to Sanders, told The New York Times that many black voters would defect to Sanders once they become more familiar with his policies, adding that the primary would be a lot closer than polls suggest.

"Bernie Sanders is killing the game when it comes to young voters," he told The Times. "They're not just saying, 'I'm going to vote for him.' They're working and using social media. You'd think they're on his campaign team, and they're not."