Negotiations over U.S. President Joe Biden's 3.5-trillion-U.S.-dollar spending bill have hit a "stalemate," leaving the fate of his entire first-term agenda up in the air.

The president on Friday said negotiations have hit a deadlock amid heated disagreements between progressives and moderates in his party, which could sink his massive social spending bill.

Biden said he believed his party would ultimately reach a consensus on a 1.2-trillion-dollar infrastructure bill backed by Republicans, as well as his 3.5-trillion-dollar social spending package.

"Now we are at this stalemate," and "we are going to have to get these two pieces of legislation passed," Biden said Friday at the White House.

But it remains unknown how that will happen, as progressives and moderates in the Democratic Party are digging their heels in, and it remains unclear whether any of them will budge.

That leaves the fate of Biden's core economic and social agenda unknown.

"If Democrats pass a bill of any significant size, it will be a plus for his poll numbers. If Democrats are not able to pass a bill due to internal divisions, that would be a major blow to Biden's presidency and his public support," Darrell West, a senior fellow at Brookings Institution, told Xinhua.

Clay Ramsay, a researcher at the Center for International and Security Studies at the University of Maryland, told Xinhua that if Biden simply passes the smaller bipartisan infrastructure bill, that will not be enough for the president to bounce back in the polls.

Among Americans, 45.7 percent approve of the job Biden is doing, and 50.3 disapprove, according to Friday's Real Clear Politics average of polls.

"It will not, because in the public, Democrats are also more worried about Biden now and some are moving from a 'strongly support' to a 'somewhat support' stance," said Ramsay.

Christopher Galdieri, an assistant professor at Saint Anselm College, said he does not think passing the 3.5-trillion-dollar bill will directly translate into a boost in the polls, "but it will improve his reputation in DC and with voters as someone who is able to get things done."

"The last month or so has been one story after another in which the administration is not driving events but instead looks responsive to others. So a big legislative win would turn that perception around, I think," Galdieri told Xinhua.

Indeed, the Delta variant of COVID-19 is surging in the United States among those who have declined to get vaccinated.

While around half of the U.S. population became vaccinated in a matter of months, millions of others do not want to get the jab. That, plus the botched Afghanistan withdrawal, are dragging down the president's polling numbers.

An article in The Hill, a U.S. political publication, argued that Biden is badly in need of a win.

"If anyone needs a big win right now, it's the embattled 46th president," Joe Concha, a contributor, contended.

A Gallup article released earlier this week found that among all U.S. presidents after WWII, only former U.S. President Donald Trump saw lower ratings at a similar point in his presidency.

Pollsters point to the administration's bungled withdrawal from Afghanistan as the main reason for the decline, as well as the surging Delta variant among the unvaccinated.

"Two-thirds of Biden's slide among independents since he took office has occurred in the past three months," Gallup wrote earlier this week.

Meanwhile, the midterm elections are over a year away, but experts said Biden is navigating dangerous political waters.

That is because the midterms act as a referendum on the U.S. presidency.

Mary Avery, an office administrator in the U.S. state of New Jersey, said Biden has done a "terrible" job, citing the withdrawal in Afghanistan.