ST. MATTHEWS — Cedric Richmond was tired but motivated.
The Louisiana congressman, a former chairman of the Congressional Black Caucus, had risen at 4 a.m. Saturday morning, kissed his son on the forehead and flown to South Carolina to spend a day traversing the state to rally support for former Vice President Joe Biden.
But to Richmond, a national co-chairman of Biden's campaign, the long hours on the road after a full week in Washington were worth it to boost "somebody who can heal this country, somebody who has the experience to restore our standing on the world stage."
"South Carolina is very important in this process, if not the most important state," Richmond said that afternoon aboard Biden's campaign bus. "Before Super Tuesday, it is a great reflection of the country. ... This is a must-win if I've ever seen one, and so I've decided to sacrifice every free moment to make sure that we win."
Over the course of a four-day "Soul of the Nation" bus tour of Biden campaign surrogates, including personal testimonials from his sister and longtime adviser Valerie Biden Owens, Biden's campaign sought to lock down support in his strongest early-voting state as he continues to take hits from Democratic primary foes.
After the bus tour, Biden himself returned to South Carolina for a two-day trip that included speaking at a Bethlehem Baptist Church service in Columbia and a Democratic oyster roast in Orangeburg on Sunday, where he told the crowd that "our very democracy, everything that's made America America, is at stake."
On Monday, Biden will be flanked by a half dozen of his chief rivals for the Democratic nomination at the annual Martin Luther King Day at the Dome commemoration in Columbia — a visual demonstration of a contested race that Biden's opponents say is far from over with 40 days left until the Feb. 29 primary.
The trip may mark Biden's last visit to South Carolina for some time as national attention turns toward Iowa's Feb. 3 caucuses and New Hampshire's Feb. 11 primary, a pair of states where polls have shown a much closer and more volatile race.
It also came as several of Biden's Democratic opponents have been nipping at his heels in recent weeks.
With a massive advertising blitz, billionaire businessman Tom Steyer has risen in polls of South Carolina Democrats by arguing he's the best positioned to challenge Trump's claims on the economy and the only candidate treating climate change with the urgency it needs.
Meanwhile, Bernie Sanders' campaign has become increasingly blunt in its critiques of Biden's record, particularly on issues with impact in the African American community from school integration to welfare reform.
During an activist rally at the University of South Carolina on Sunday afternoon, Sanders surrogate Phillip Agnew rejected the notion that Biden would be the most electable nominee.
"This is the only campaign that can elicit the type of excitement from working class people that we're going to need to beat Donald Trump," Agnew said. "You can't counteract what's coming from the right with a lukewarm, 'maybe' politics."
Symone Sanders, a senior adviser on Biden's campaign, attributed the hits on Biden to other campaigns "getting desperate" as the first primaries approach.
"For nine months, people have tried to disparage Joe Biden's character, they've been predicting our campaign is collapsing and they've thrown everything they could at him and nothing's stuck," Sanders said. "So I think what we can read from that is Vice President Biden is durable and voters feel like they know Joe Biden."
In St. Matthews, Sanders told a couple dozen voters that she views South Carolina's primary less as a "firewall" for the campaign and more as a "launching pad" into the states that follow.
Many of the events were filled with older African American voters, a crucial demographic in South Carolina given their high levels of voter turnout and one that Biden performs particularly well with in most polls.
They featured only occasional talk of policy specifics, instead mostly touting Biden's character and experience. That emphasis from Biden's campaign surrogates was reflected in the voters who attended the events, many of whom cited Biden's "warmth" and connection to Obama as their top reasons for backing him.
"Number one, he's a decent man," said Idella Felder, a retired receptionist from St. Matthews. "I'm tired of seeing a president on national television telling all of these fibs. I think Biden has the qualifications to get the country back on track."
Time and again, voters said they were willing to hear out other candidates, but their decision to vote for Biden had already been solidified. Several said they decided to vote for Biden the day he entered the race.
"I like (U.S. Sen. Elizabeth) Warren's toughness," said Thomas Chambers, an Army veteran from North Charleston. "But I feel like I know Joe. You know how sometimes with people you can just feel where their heart is? Joe's heart is with the people."
Linda Whetsell of Summerville said she’d been “bombarded” by calls from other campaigns in recent weeks, but she had heard nothing to convince her to ditch Biden — and doubts she ever will.
“Everybody knows the issues, but he’s the one with the experience to get it done,” said Whetsell, 66, before Biden spoke at the oyster roast Sunday. “If he can’t do it after working with Obama, none of them can.”