Sanders hits highest support since August

Sen. Bernie SandersBernie SandersBiden pushing to cancel Keystone XL pipeline as soon as he takes office: reports Biden tax-hike proposals face bumpy road ahead Senate Democrats leery of nixing filibuster MORE’s (I-Vt.) support has climbed to its highest level in nearly five months, according to a new Hill-HarrisX poll of the Democratic presidential primary race.

The nationwide survey released Tuesday showed that 19 percent of respondents support Sanders, which makes him just one point shy of his previous high of 20 percent in the August 16 poll.

Former Vice President Joe BidenJoe BidenWoman accused of trying to sell Pelosi laptop to Russians arrested Trump gets lowest job approval rating in final days as president Trump moves to lift coronavirus travel restrictions on Europe, Brazil MORE, meanwhile, maintained the top spot with 29 percent support. Sen. Elizabeth WarrenElizabeth WarrenBiden's minimum wage push faces uphill battle with GOP What to watch for in Biden Defense pick's confirmation hearing Biden selects Gensler for SEC chair, Rohit Chopra to lead CFPB MORE (D-Mass.) placed third, holding at 11 percent.

After rising to third place alongside Warren in the Jan. 3 survey, former New York City Mayor Michael BloombergMichael BloombergBiden selects Gina Raimondo for Commerce chief: reports 7 surprise moments from a tumultuous year in politics NFL, politics dominate 2020 ratings MORE slipped 4 percentage points to 7 percent.

Former South Bend, Ind. Mayor Pete ButtigiegPete ButtigiegOVERNIGHT ENERGY: Senate majority offers Biden new avenues on Trump environmental rollbacks | Democrats eye action on range of climate bills | Biden pushing to cancel Keystone XL pipeline as soon as he takes office: reports Biden rolls out group of deputy secretary nominees On The Money: Retail sales drop in latest sign of weakening economy | Fast-food workers strike for minimum wage | US officials raise concerns over Mexico's handling of energy permits MORE also saw a slight dip, dropping from 6 percent to 4 percent.

Sen. Amy KlobucharAmy KlobucharGoogle completes Fitbit acquisition Hillicon Valley: Fringe social networks boosted after Capitol attack | Planned protests spark fears of violence in Trump's final days | Election security efforts likely to gain ground in Democrat-controlled Congress US Chamber of Commerce to stop supporting some lawmakers following the Capitol riots MORE (D-Minn.) and billionaire Tom SteyerTom SteyerOn The Trail: The political losers of 2020 Biden Cabinet picks largely unify Democrats — so far Late donor surges push election spending projections to new heights MORE each received three percent support. The rest of the candidates in the crowded Democratic field polled at 2 percent or less.

The survey is likely welcome news for the Sanders campaign ahead of the Iowa caucuses.

Sanders’s campaign has intensified attacks against top rivals ahead in recent months, specifically targeting Biden and Warren.

Sanders and his aides have repeatedly gone after Biden for his past positions on racial issues and his vote in favor of the Iraq War.

Jeff Weaver, a senior adviser to the Sanders campaign, issued a statement over the weekend, saying he found it “appalling” that the former vice president “still refuses to admit he was dead wrong on the Iraq War.”

Former Secretary of State John KerryJohn KerryFor Joe Biden, an experienced foreign policy team Biden's trade policy needs effective commercial diplomacy Biden taps ex-Obama aide Anita Dunn as senior adviser MORE later accused Sanders of "distorting" Biden's record on Iraq.

Sanders’s campaign has also engaged in a dust-up with the Massachusetts senator's campaign, reportedly telling prospective voters that the candidate is a weak election choice because she only appeals to white educated liberals.

The back-and-forth eventually culminated with Warren’s claim that Sanders had told her during a 2018 meeting that a woman could not win a general election race against President TrumpDonald TrumpGiuliani used provisional ballot to vote in 2020 election, same method he disparaged in fighting to overturn results Trump gets lowest job approval rating in final days as president Fox News' DC managing editor Bill Sammon to retire MORE.

Both feuds could come to a head in Tuesday night’s Democratic primary debate. 

Sanders is among the six candidates set to take the stage in Iowa. The event marks the last debate before the Hawkeye State holds its caucus on Feb. 3.

The Hill-HarrisX survey was conducted among 451 Democratic voters and Democratic-leaning independents. It has a margin of error of plus or minus 4.5 percentage points.

—Tess Bonn