Asked by reporters as he left the White House, "Do you support passing COVID relief through budget reconciliation?," Biden answered, "I support passing COVID relief with support from Republicans if we can get it. But COVID relief has to pass. There’s no ifs, ands or buts."
Biden has repeatedly called for a bipartisan approach, reaching across the aisle to try to rally support only to be stonewalled by opposition. A few Republicans have expressed a willingness to consider a far smaller, "targeted" package, but none has come close to supporting the level of spending advocated by Biden and congressional Democrats.
But Biden, who met with newly-installed Treasury Secretary Janet Yellen Friday morning, said he's focused on providing broader relief than most Republicans can stomach.
"We have learned from past crises; the risk is not doing too much, the risk is not doing enough," Biden said.
Earlier this week, Senate Majority Leader Chuck Schumer signaled that Democrats are preparing to move forward with budget reconciliation: a complex, fast-track process that requires just a simple majority to pass legislation rather than the usual 60 votes needed to overcome a filibuster and move forward. In a Senate now split 50-50, the procedure could allow Democrats to pass legislation without a single Republican in favor, with Vice President Kamala Harris able to cast a tie-breaking vote.
"If our Republican colleagues decide to oppose this urgent and necessary legislation, we will have to move forward without them," Schumer said Thursday. "We have a responsibility to help the American people fast."
A vote on a Senate budget resolution, which is the first step in beginning the reconciliation process, is expected next week in the Senate. It would then go to the House for consideration.
Republicans are calling foul, warning Democrats that using reconciliation to pass COVID relief will diminish Biden's calls for unity throughout his campaign and in his inaugural address.
"If reconciliation is chosen as the COVID legislative vehicle, it will make the Inaugural speech by President @JoeBiden ring very hollow," Sen. Lindsey Graham, R-SC., tweeted Friday.
Graham urged the administration to pursue a bipartisan path forward.
"It would take effort, but apparently very little effort is being shown by the Biden Administration when it comes to bipartisanship on COVID relief."
Sen. Todd Young, R-Ind., echoed Graham, telling reporters Thursday that pursuing reconciliation is "going to send a signal to America, and to the Republicans throughout Congress, that this President's message of unity was rhetoric as opposed to substance."
Reconciliation has been used by both parties to pass controversial priorities in the past. According to the Congressional Research Service, the process has been used 25 times since its first use in 1980.
As Republicans continue to sour on the Biden plan, Democrats are left with few options but to go it alone to deliver on Biden's key campaign promise, despite early consensus building efforts from the bipartisan congressional group that helped craft the last COVID-19 relief bill.
That group spoke with White House National Economic Council head Brian Deese last weekend, and some have had additional private conversations. Republicans left urging the administration to tailor their approach more narrowly.
Discussions about reconciliation are "certainly not helpful" to the group's efforts, Sen. Susan Collins, R-Maine, who is part of the bipartisan effort, said Thursday.
Sen. Rob Portman, R-Ohio, was also part of the bipartisan conversations and said he's been working on "trying to convince the administration that they ought to work with us rather than jam something through the Congress with a strictly partisan vote."
There is an appetite among some GOP senators for targeted legislation that includes funding for vaccine development and distribution.
"The most appealing thing I've heard so far would be to break out the vaccine healthcare implementation part and have a bill that probably would be almost universally passed," Sen. Roy Blunt, R-Mo., said. "But I don’t have any particular reason to believe that that idea, which came from one of our friends on the Democratic side, will move forward."
Many in the GOP conference feel that the $920 billion allocated in the last COVID relief package should be more fully disbursed before another large aid measure is passed. That legislation extended protections for renters, jobless benefits, and other key provisions. Those extensions don't begin expiring for another few weeks.
"I'm not sure I understand why there's a grave emergency right now," Portman said Thursday.
But Democrats counter that time is of the essence, and administration officials made clear this week that the relief package would not be split in two.
Sen. Dick Durbin, D-Ill., cited the March 14 deadline when federally-enhanced unemployment insurance benefits - provided in last month's aid package - expire as reason for the rush. The Biden plan would increase those weekly benefits from $300 to $400 and extend the aid through September.
Some Democrats, like Sen. Tim Kaine, D-Va., have urged Republicans to focus on the priorities in the budget bill that will appeal to them.
And Sen. Chris Murphy, D-Conn., noted that reconciliation does not have to be a purely partisan approach, though history shows that the procedure rarely attracts bipartisan support.
"Reconciliation doesn't require that you only get 50 votes, so there is no reason that Republican's couldn't vote for the package, even if we use reconciliation."
Reconciliation has a long way to go to get across the finish line, though. Democrats are looking to get measures such as a more than doubled federal minimum wage - to $15 per hour - through reconciliation, a feat that even House Budget Committee Chairman John Yarmuth, D-Ky., recently called "a stretch." The budgetary tool is designed to be used in these three areas: direct spending (entitlements, food stamps, other mandatory spending), revenue (taxes), and deficit reduction.
And the wage hike is sure to be challenged by Republicans who say that businesses crippled by the pandemic could not afford the increase.
Still, Sen. Bernie Sanders, I-Vt., the incoming Senate Budget Committee chairman, insisted that he and his budget experts intend to show that a $15-per-hour minimum wage increase would result in "dramatic deficit reduction."
"I think the argument is that raising the minimum wage is going to have a profound impact on the budget, all across the budget. ... If you're making 15 bucks an hour, you're less likely to have to go on to one form or another of public assistance."
ABC News' Molly Nagle, Sarah Kolinovsky and Ben Gittleson contributed to this report