Republicans brimmed with pride over the $900 billion stimulus package taken up by Congress on Monday, with Senate Majority Leader Mitch McConnell calling it “a historic bipartisan rescue package” and Sen. Dan Sullivan (Alaska) predicting it would be remembered when “the history of this challenging year is written.”

President-elect Joe Biden saw it differently, calling the deal merely a “down payment.”

Biden’s assessment, made repeatedly in recent weeks, echoes the view of many Democrats who see the bill as the beginning of a negotiation, not the end. The notion that more aid is necessary — Biden at times has said talks should start as early as January — sets up perhaps the first major legislative test for the new president and his self-proclaimed negotiating skills.

It’s a challenge made greater now that Congress has approved new spending in the areas where common ground was relatively easy to find. There is also an expectation that many Republicans will become more skeptical of big-ticket spending after President Trump leaves the White House.

Biden has consistently said that bolstering the economy will be one of his four top priorities — along with ending the pandemic, addressing climate change and promoting racial justice — suggesting he will put a strong emphasis on new spending. He has been vague about what he would like in a new package, but it would probably include aid to cities and funds to prepare for opening public schools.

That push, however, will clash with an energized Republican Party eager to reestablish its fiscally conservative bona fides. McConnell (R-Ky.) has signaled that he recognizes additional negotiations are likely but said it would be difficult to finalize another package.

Privately, many in Biden’s party agree it will be hard to persuade Republicans to reopen the debate after the protracted, often tortuous negotiation that led to this last-minute deal days before Christmas.

Biden declined to take detailed questions from reporters Monday after he received his coronavirus vaccination at Christiana Hospital in Newark, Del. But an official on Biden’s transition, who spoke on the condition of anonymity because the person was not authorized to speak publicly, said the president-elect wants additional money for “supporting the covid response effort, reopening schools and helping families, businesses, and state and local governments.”

Biden has been blunt in recent weeks that he considers Congress’s current package far from enough to tackle the widespread economic damage caused by the pandemic. “I’ve made it real clear,” Biden told reporters in Wilmington, Del., earlier this month. “This is not the end of the deal.”

Senior Republicans viewed Biden’s victory as key to unlocking the current deal, because it gave Democrats a credible justification for backing off their previous multi­trillion-dollar demands that GOP lawmakers had no intention of meeting. Chief among them was their insistence that struggling state and local governments badly need a cash infusion to help provide vaccine distribution and other services.

But for many Republicans, the approximately $900 billion package that came together this week represents the outer limit of what they are willing to accept.

Furthermore, there is no obvious deadline to compel action, often a requirement on Capitol Hill. The bill was forced to the finish line by a looming government-shutdown deadline and a pair of Senate runoff elections in Georgia on Jan. 5, as Republican leaders were anxious that the lack of a relief package was hurting Sens. Kelly Loeffler (R-Ga.) and David Perdue (R-Ga.).

The clamor of rank-and-file lawmakers faced with returning home for Christmas without a deal in hand also created pressure.

Similar pressures are on the immediate horizon next year. Instead, the impetus for further relief, if any, is likely to be driven by the pace of the economic recovery and whether employment and growth rebound in the weeks after Biden takes office.

The president-elect has suggested the economy may not rebound immediately, saying that would drive Republicans to the negotiating table. “As things get worse, they’re going to find that there’s an overwhelming need,” Biden said recently.

One potential deadline comes in mid-March, when 11 weeks of additional jobless benefits provided in the current bill to the long-term unemployed are set to expire. But several Republican senators have signaled that even then, further action is doubtful.

“If we address the critical needs right now and things improve next year as the vaccine gets out there and the economy starts to pick up again, you know, then there’s maybe less of a need,” Sen. John Thune (R-S.D.) said last week.

One demand, however, could bring Republicans back to the bargaining table: their desire for a sweeping “liability shield” barring coronavirus-related lawsuits against businesses. GOP leaders, in the most recent round of negotiations, sought to pair that with a top Democratic priority — tens of billions of dollars in direct aid to state and local governments. In the end, both issues were dropped from the talks.

Although some Republicans have broken with party leaders to call for additional state and local aid, Democrats remain dead set against immunizing businesses from lawsuits.

Months of talks on the subject sputtered, and it could be difficult for Biden to make headway on it. But the liability issue may be his only chance to force new action, even if Republicans are unlikely to trade it for anywhere near the trillion dollars of additional stimulus Democrats want.

“I think everybody understands that Vice President Biden is going to ask for another bill, so we will have another chance to revisit it probably pretty soon,” Sen. John Cornyn (R-Tex.), a key proponent of the liability shield, said Monday.

Biden has largely avoided naming specific items or a spending target for the next package, saying that would be a bad negotiating strategy. “I’ve learned, after hanging around in this business for a while, the last thing you do before you begin a negotiation is lay out a drop-dead marker,” Biden said earlier this month.

Asked if he believes the right number for the next package is in the billions or trillions, Biden responded: “Hundreds of billions of dollars.”

Still, Biden has sketched out some of his priorities over the past few weeks, including additional funding for state and local governments. The current package includes none of this spending despite pleas from states such as New York and Illinois, whose governors have warned that they may need to raise taxes, lay off public-sector workers or cut spending on critical government programs to break even entering next year.

Biden has cast the state and local aid as critical for jobs, saying it is important that the federal government provide help to local governments to prevent layoffs of public employees including teachers, firefighters and other first responders.

Biden also said recently that “it would be better” if the deal included $1,200 checks for low-income people. The current bill includes $600 checks for people making less than $75,000 a year — which alone cost $164 billion or about as much as the new state and local aid Democrats have sought.

Democratic leaders agree. In a statement late Monday, House Speaker Nancy Pelosi (D-Calif.) penned a letter to her colleagues about the legislation that laid a marker for the next round, noting that “state and local budgets are still overwhelmed by coronavirus expenses and revenue losses.”

Biden has also said Americans should not be evicted from their homes during the coronavirus crisis. The current compromise includes a measure that extends a moratorium on evictions through the end of January.

Biden has said extending unemployment insurance is necessary “so they can continue to feed their families.”

This week’s package allows for a $300-per-week additional unemployment benefit until at least mid-March, about half of the $600-per-week additional benefit that Congress enacted last spring.

The bill also extends a special program for gig workers.

Asked whether he would have any leverage to bring Republicans skeptical about the price tag back to the table, Biden said Americans will be desperate for more help.

“The country’s going to be in dire, dire, dire straits,” Biden said. “We’ll be in dire trouble if we don’t get cooperation, and I believe we will.”

Biden also offered a smidgen of bipartisan bonhomie on Monday, perhaps practicing his negotiating skills. As he received his vaccination, Biden praised the White House, saying, “I think the administration deserves some credit for getting this off the ground.”