Former Vice President Joe Biden Joe BidenBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Harris faces pivotal moment with Supreme Court battle MORE’s commanding lead in the polls is putting pressure on Democratic lawmakers to endorse him, even though the first primary contest is eight months away.

Sen. Chris Coons Christopher (Chris) Andrew CoonsMurkowski: Supreme Court nominee should not be taken up before election Battle lines drawn on precedent in Supreme Court fight Sunday shows - Ruth Bader Ginsburg's death dominates MORE (D-Del.), one of Biden’s surrogates on Capitol Hill, has touched base with colleagues about endorsing Biden, who is certain to come under attack from more liberal rivals in the run-up to the Iowa caucus and New Hampshire primary.

Sen. Bob Casey Robert (Bob) Patrick CaseySecond GOP senator to quarantine after exposure to coronavirus GAO report finds brokers offered false info on coverage for pre-existing conditions Catholic group launches .7M campaign against Biden targeting swing-state voters MORE (D-Pa.), who has also endorsed Biden, is arguing that the former Delaware senator can win the pivotal battleground of neighboring Pennsylvania, highlighting what many Democrats see as his greatest asset: electability.

ADVERTISEMENT

But many lawmakers are holding back, especially in the Senate, where Democrats are worried about offending colleagues who are also seeking the party’s nomination. Right now there are seven senators competing with Biden for the nomination, including Sens. Bernie Sanders Bernie SandersOutrage erupts over Breonna Taylor grand jury ruling Dimon: Wealth tax 'almost impossible to do' Grand jury charges no officers in Breonna Taylor death MORE (I-Vt.), Kamala Harris Kamala HarrisHarris faces pivotal moment with Supreme Court battle Nearly 40 Democratic senators call for climate change questions in debates Joe Biden has long forgotten North Carolina: Today's visit is too late MORE (D-Calif.) and Elizabeth Warren Elizabeth WarrenDimon: Wealth tax 'almost impossible to do' CNN's Don Lemon: 'Blow up the entire system' remark taken out of context Democrats shoot down talk of expanding Supreme Court MORE (D-Mass.).

The Democratic primary in 2020 is playing out much differently than it did in 2016, when then-frontrunner Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE locked up early support, gaining an advantage among superdelegates that made it much tougher for rival Sanders to win the nomination.

Superdelegates, who are made up of Democratic Party officials and officeholders, will wield much less power next year than they did in the competitive primaries of 2008 and 2016. As a result of reforms adopted in August, superdelegates will not participate in the first round of voting for the nominee at the 2020 convention in Milwaukee. Their votes will come into play only if the first ballot does not yield a nominee.

“I’m just asking my colleagues, respectfully, what their perspective is on the presidential primary,” said Coons, who said he is focusing on senators who don’t appear to be leaning toward any White House hopefuls yet.

“Given how many of our colleagues are candidates, I’m not twisting any arms. I’m not making a hard sell but I’m exploring with colleagues who clearly are not committed to any particular candidate,” he said.

Casey said he’ll reach out to colleagues “at some point” but noted “it’s pretty early.”

ADVERTISEMENT

But the senior senator from Pennsylvania is already making the argument that Biden is well positioned to win his state and its 20 electoral votes, a must for Democrats if they are to defeat President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE.

“Importantly, I think he can carry Pennsylvania,” Casey said, highlighting one of Biden’s biggest selling points with fellow Democrats.

Casey said he’s not sure some of Biden’s rivals can beat Trump in the Keystone State. “I’m not sure how many I would put on the list I’m certain can win,” he said.

Biden has increased his lead over Sanders, who often places second in national polls, since announcing his candidacy in mid-April, defying predictions that he might peak on the first day of his campaign.

Monmouth University and Morning Consult polls published around the time Biden announced his third White House bid showed him leading the Democratic field by high single digits. More than a month later, his average polling lead is 18 points.

Sen. Tom Carper Thomas (Tom) Richard CarperThe conservative case for phasing out hydrofluorocarbons Democrat asks for probe of EPA's use of politically appointed lawyers Overnight Energy: Study links coronavirus mortality to air pollution exposure | Low-income, minority households pay more for utilities: report MORE (D-Del.), one of four senators endorsing Biden, says he puts “a lot” of stock in the early numbers.

“I’ve seen some impressive polling data for a while and the numbers are actually getting better not worse, so it’s encouraging,” he said.

Biden’s strength in the polls is all the more impressive because he had to weather a scandal right out of the gate when several women, including Lucy Flores, a former candidate for lieutenant governor in Nevada, accused him of inappropriate touching and invading their personal space at a public event years ago.

Carper said electability is an overriding concern for many Democrats right now and sees Biden as someone who can bring the party together and beat Trump.

“There’s a hunger among Democrats to win. There’s a hunger for someone who can unite our party and unite our country. And there’s a hunger for someone who can help restore our standing in the world,” he said.

Biden’s gathering strength and the desire by some to unify the party as soon as possible is putting pressure on other Democrats to consider endorsing the front-runner.

In addition to Coons, Casey and Carper, Sen. Doug Jones (D), a centrist from Alabama, has also announced his support, giving Biden more Senate endorsements than any other Democratic candidate.

Biden’s campaign scored a coup this past week when it announced that Rep. Cedric Richmond Cedric Levon RichmondRep. Bill Pascrell named chair of House oversight panel Rep. Cedric Richmond set to join House Ways and Means Committee Biden campaign ratchets up courting of Black voters, specifically Black men MORE (D-La.), a former chairman of the Congressional Black Caucus, will serve as its national co-chairman.

That was a blow to Harris and Sen. Cory Booker Cory Anthony BookerBipartisan praise pours in after Ginsburg's death DHS opens probe into allegations at Georgia ICE facility Democratic lawmakers call for an investigation into allegations of medical neglect at Georgia ICE facility MORE (D-N.J.) -- both members of the black caucus who are also running for the nomination.

Richmond told The New York Times that he picked Biden “because I thought he was the best person to take on President Trump and beat him.”

Senate Democratic Whip Dick Durbin Richard (Dick) Joseph DurbinFeinstein 'surprised and taken aback' by suggestion she's not up for Supreme Court fight Grand jury charges no officers in Breonna Taylor death Democrats shoot down talk of expanding Supreme Court MORE (Ill.), who was the first Senate Democrat to endorse then Sen. Barack Obama Barack Hussein ObamaThe Memo: Trump's strengths complicate election picture Obama shares phone number to find out how Americans are planning to vote Democrats' troubling adventure in a 'Wonderland' without 'rule of law' MORE ahead of the 2008 presidential election, said colleagues may be feeling some pressure to announce their support as early as possible if It seems increasingly likely that Biden will win the nomination.

“It’s possible. I was on the other side with Obama [in 2007] and talked to a lot of members about getting on the train before it leaves the station,” he said, recalling that for months he was the only senator willing to endorse the party’s eventual nominee.

Durbin, however, said he’s staying neutral for the time being.

Lawmakers who make early endorsements are more likely to receive strong consideration for Cabinet positions.

Trump rewarded former Sen. Jeff Sessions Jefferson (Jeff) Beauregard SessionsGOP set to release controversial Biden report Trump's policies on refugees are as simple as ABCs Ocasio-Cortez, Velázquez call for convention to decide Puerto Rico status MORE (R-Ala.), who for months was the only senator to endorse his candidacy, by naming him attorney general, although the relationship quickly soured once he was in office.

Former Sen. Ken Salazar (D-Colo.), who sided with Obama when he was battling Clinton for superdelegates in 2008, was later named as secretary of the Interior Department.

Many Democratic senators, however, say they want to see how the debates and early primary contests in Iowa and New Hampshire play out before making a public endorsement.

Several who spoke on condition of anonymity with The Hill said they were worried about offending their other colleagues in the race, who might be less inclined to work with them if they back a rival.

“I’m just going to follow it and wait and see,” said one Democratic senator. “I think we’re going to have a couple of primaries to get a feeling where this thing is going to land.”

“When you have a candidate who’s so far in front like that, that’s name ID. He was the vice president for so long. That always happens in races, whether it’s a Senate race or a House race,” the lawmaker added, questioning whether Biden’s lead will be sustainable into the early part of 2020.

“If you’re in Senate working every day to try to get things passed and deal with everybody, it’s a disaster to take sides in a presidential race. It hurts your ability to keep lines of communication open and keep things moving,” the senator added.

A second Democratic senator also raised doubts about Biden’s ability to keep his big lead going.

“I am not persuaded that his polling lead is not written in the wind,” the lawmaker said.

The senator also expressed misgivings about how an endorsement would be received by Senate colleagues.

“I’m not going to screw one of my colleagues,” the lawmaker added.