WASHINGTON (NYTIMES) - A fragile bipartisan infrastructure deal appeared to be moving forward once again Sunday (June 27), as moderate Republicans said they had been reassured that President Joe Biden would not hold it hostage while Democrats simultaneously work on a larger, partisan economic package.

After 48 hours of chaos, the statements by leading Republicans prompted a sigh of relief for the White House, where Mr Biden and top aides had worked through the weekend to keep the eight-year, US$1.2 trillion (S$1.61 trillion) investment to rebuild the nation's infrastructure from falling apart.

GOP negotiators even suggested that they could now begin drafting the Bill and said they believed it would win enough Republican votes to pass the Senate next month.

"The waters have been calmed," said Senator Mitt Romney.

Still, the whole episode underscored just how precarious a path the president and his allies face in the months ahead, as they try to steer the two separate and costly spending plans into law.

They have laid out a complex strategy in which the success of each Bill hinges on the other and the balancing of priorities between not only Republicans and Democrats, but within the Democratic Party itself.

While the bipartisan Bill can be passed through regular order if it retains enough Republican support, Democrats plan to use a fast-track budget process known as reconciliation to bypass the 60-vote filibuster threshold and unilaterally enact the rest of Mr Biden's proposal, which includes tax increases, sweeping climate plans, health care provisions and investments in child care.

If they can pull off both, Mr Biden could burnish his reputation as a bipartisan deal-maker and ensure that much of his economic agenda is locked in place.

The immediate cause for Republican concern came Thursday, just hours after the president and lawmakers from both parties unveiled with great fanfare their plan to invest in crumbling roads, bridges, high-speed Internet and green projects.

Speaking with reporters later that day, Mr Biden said he would not sign the bipartisan deal without Congress passing a much more expensive set of tax increases and spending programmes that conservatives loathe.

Republicans, who doubt Democrats can secure the votes needed to pass the second partisan package, balked. They said that they never would have signed onto a deal strictly conditioned on the success of policies they oppose, and Mr Biden's team was forced to clean up the comments.

After a series of private phone calls, the president issued a lengthy statement Saturday clarifying that he never meant to threaten a veto and conceding that Republicans were "understandably upset."

"I was very glad to see the president clarify his remarks because it was inconsistent with everything we had been told along the way," Republican Senator Rob Portman said on ABC's "This Week."

"I'm glad they've now been de-linked and we can move forward with a bipartisan bill that is broadly popular not just among members of Congress but the American people."

Senator Bill Cassidy concurred on NBC's "Meet the Press," calling the framework agreed to by the two parties "a great deal."

"It is actually going to provide the infrastructure that American people want, that they need, that will make our country more prosperous for all Americans, so I hope it's enough," he said of Mr Biden's clarification. "But I'll continue to work for the Bill."

For now, the bipartisan deal seems to be having the effect on Democrats that Mr Biden and party leaders on Capitol Hill were also hoping for. Democratic leaders are trying to hold together the narrowest of majorities in the House and Senate, and some of their most moderate members insisted on trying to find bipartisan common ground on the president's vast domestic agenda wherever they could.

Pleased that a bipartisan package he helped craft would be moving forward, Senator Joe Manchin of West Virginia, a key Democratic swing vote, said Sunday that he was prepared to back a larger Bill using the fast-track process to get around Republicans.

He said he was "all for" using it to address "human infrastructure" and was willing to raise corporate tax rates to 25 per cent from 21 per cent, and capital gains taxes to 28 per cent for top earners to finance it.

"We've worked on the one track. We're going to work on the second track. There's an awful lot of need," Mr Manchin said on ABC.