Members of the US Congress voted 67-32 on Wednesday to advance a bipartisan infrastructure bill in the Senate, starting what is expected to be a fierce debate before another vote on the full passage of the package.
A total of 17 Republicans joined all 50 Democrats in the Senate to begin the debate on the infrastructure proposal, which would pump historic levels of federal funding into fixing US roads, bridges and waterways and expand clean energy programmes.
The bipartisan measure, including some $550 billion in new spending, came together after two months of often-tense negotiations that US President Joe Biden and his Democrats wanted to see concluded before Congress breaks for its August recess.
The deal will create millions of good jobs and make the US economy more robust, sustainable, resilient and just, the White House said in a statement.
Mr Biden called it "the most significant long-term investment in our infrastructure and competitiveness in nearly a century".
"This deal signals to the world that our democracy can function, deliver and do big things," he said, and added that the plan had the potential to "transform America and propel us into the future".
The deal will make the largest-ever federal investments in public transit and drinking and wastewater infrastructure; the largest funding of passenger rail since the creation of Amtrak; and the largest investment in bridges since the creation of the nation's highway system.
It also helps tackle the climate crisis by investing historic amounts in clean energy projects and electric vehicle infrastructure, such as the electrification of thousands of school and transit buses nationwide and forming an authority to oversee the creation of a clean electricity grid.
The bipartisan group negotiating the blueprint appears to have overcome a key hurdle: how to pay for the huge spending outlay.
The White House said revenue would come from redirecting unspent Covid emergency relief funds, boosting corporate fees and strengthening tax enforcement on cryptocurrencies.
"I'll be voting to begin debate on the bipartisan infrastructure package," Kevin Cramer, a Republican senator, tweeted earlier on Wednesday. "While I can't say I'll vote for final passage, we need to keep this proposal moving forward and work to amend it if necessary."
The bill will still need to clear the House of Representatives, where it could face resistance from progressive Democrats.
Some have said they would not sign on unless Biden's ambitious $3.5 trillion budget package — including once-in-a-generation spending on health care, education, social welfare and climate action — passes the Senate.
The bipartisan agreement was announced shortly after Mr Biden travelled to the Pennsylvania factory of a lorry maker where he called on Congress to pass tougher "Buy American" policies that would boost the US-made content in $600bn in government purchases.
Mr Biden's plan comes as the Covid-19 pandemic has highlighted weaknesses in global supply chains that have left US markets short of critical products and materials, including semiconductors, building materials and toilet paper.
The administration is proposing to increase the 55 per cent US-content requirement in the Buy American Act for supplies to the federal government to 60 per cent in the short term, and gradually to 75 percent.