U.S. presidential candidate Bernie Sanders has reclaimed the lead in the New Hampshire primary. Sander is leading with 21 percent of likely Democratic voters, followed by Senator Elizabeth Warren at 18 percent and former Vice President Joe Biden at 15 percent, according to the Granite State Poll conducted by the University of New Hampshire and co-sponsored by CNN.

The poll released Tuesday shows South Bend, Indiana, Mayor Pete Buttigieg at 10 percent and a three-way tie for fifth place: entrepreneur Andrew Yang, Sen. Amy Klobuchar of Minnesota and Rep. Tulsi Gabbard of Hawaii, each at 5 percent.

Politico notes that Biden has lost 9 points since the previous UNH poll, published in July - when Biden had a slight advantage over Sanders and Warren, who were tied for second place with 19 percent each. Sanders, who suffered a heart attack in early October, won the New Hampshire primary in 2016, which propelled his strong challenge against Hillary Clinton.

Biden is expanding his presidential campaign footprint in Super Tuesday states and a general election battleground in the latest sign that Democrats’ top White House contenders foresee a potentially lengthy nominating process in 2020.

The former vice president is hiring a top national campaign aide to focus on March 3 Super Tuesday primaries, along with state-based directors in California and Massachusetts and a senior adviser for Florida.

Warren and Sanders, who have joined Biden as Democrats’ top tier, have made significant investments already in Super Tuesday. But the Biden campaign believes his current coalition of support is more racially and geographically diverse than his opponents’ and will boost his delegate haul on Super Tuesday and in the primaries that follow.

The early jockeying in states that fall later in the primary calendar underscores how much of a delegate-by-delegate fight Democrats could end up having well after the first four nominating states of Iowa, New Hampshire, Nevada and South Carolina have cast their primary and caucus ballots.

“We’ve always viewed Super Tuesday and beyond as our path to the nomination,” said Pete Kavanaugh, a top Biden aide who oversees the campaign’s state operations and overall delegate strategy.

The hires, Kavanaugh told The Associated Press, “are a reflection of the delegates at stake” beyond the initial four states that command so much media attention and travel time from candidates.

Molly Ritner, a veteran of different Democratic Party roles, will coordinate Biden’s Super Tuesday campaigns from a post at his Philadelphia headquarters. Ritner most recently was political director for House Democrats’ campaign arm but left in a staff shakeup. Jessica Meija, former a top political strategist for Emily’s List, will lead Biden’s California campaign. California has more than 400 delegates at stake or more than 20% of the 2000 or so that will be needed to win the nomination. (The Democratic National Committee has not finalized the delegate counts for the 50 states, territories and Democrats Abroad.)

Biden’s campaign in Massachusetts, Warren’s home state, will be led by John Laadt. An aide to Hillary Clinton’s 2016 presidential campaign, Laadt most recently managed Boston Mayor Marty Walsh’s 2017 reelection campaign.

Coming after recent campaign finance disclosures showing Biden with much less cash on hand than Warren and Sanders, the hiring moves serve as an almost defiant answer from the former vice president to the Democratic donors openly fretting over whether he can mount a full-fledged national operation. Biden reported having a bit less than $9 million at the end of September, compared with Warren’s $25.7 million and Sanders’ $33 million. Even Sen. Kamala Harris and Mayor Pete Buttigieg, candidates with more ground to gain, had more money on hand than Biden.

“This is a marathon,” Biden said in a CBS “60 Minutes” interview broadcast Sunday, adding that he is “not worried about being able to fund this campaign” and still sees himself as the clear front-runner.

The polls suggest a more complicated dynamic.

Biden has led most national polls since he joined the race in April, but he’s slipped some as other candidates, most notably Warren, have risen. Warren also has improved her position considerably in Iowa, New Hampshire and Nevada, while Sanders, making his second presidential bid after finishing as runner-up for the 2016 nominating process, maintains a considerable base.

Polls suggest, however, that Biden has comfortable leads among non-white voters and does well among more moderate whites, while white liberals fuel Warren’s apparent momentum. The question for Warren is whether she can expand her current base to reflect the party’s diversity. For Biden, the questions are how well he does in the earliest states — Iowa and New Hampshire — that may lean more to Warren, Sanders and even Buttigieg and whether any underperformance there causes a shakeup in his coalition going forward.

Biden aides have said previously that Biden doesn’t have to win either of the first two states to win the nomination. That hasn’t happened since 1992, when then-Gov. Bill Clinton of Arkansas didn’t build momentum until the race went to his native South.

But Kavanaugh rejected the notion that Biden’s emphasis on the more diverse states is an abandonment of Iowa or New Hampshire. Kavanaugh also noted that Democrats don’t award delegates exclusively to statewide winners, in the early states or beyond, but instead use a complicated proportional distribution. Some delegates are awarded based on state results, others by congressional district results. Texas uses state Senate districts. But in every case, only candidates with at least 15% of the vote in the jurisdiction can get delegates.

Kavanaugh argued that Biden “is the only candidate” who can meet that 15% threshold in every district.

“We have been incredibly focused on the first four states,” he said. But “the math is the math.”