WASHINGTON — Battered by critics and dire opinion polls, President Joe Biden signed into law the biggest US infrastructure revamp in more than half a century at a rare bipartisan celebration in the White House on Monday.

The $1.2 trillion package will fix bridges and roads, change out unhealthy lead water pipes, build an electric vehicle charging network, and expand broadband internet. It is the most significant government investment of the kind since the creation of the national highways network in the 1950s.

“We’ve heard countless speeches… but today we’re finally getting this done,” Biden told hundreds of invitees on the White House South Lawn.

“So my message to the American people is this: America is moving again and your life is going to change for the better.”

Most of the crowd were Democrats but there was also a visible handful of Republicans. Notable among the Democrats were senators Kyrsten Sinema and Joe Manchin, two moderates who have warred with more leftwing members of the party, slowing down Biden’s agenda.

The bill is “proof that Democrats and Republicans can come together to deliver results,” Biden said. “Let’s believe in one another and let’s believe in America.”

Infrastructure spending is popular, but the goal eluded Biden’s predecessor Donald Trump for four years, turning his administration’s frequent promises of an imminent “infrastructure week” into a running joke.

Even now, Biden had to fight for months to get his squabbling Democratic Party to vote, risking a humiliating failure.

Democrats only narrowly control a bitterly divided Congress, but in a scarce moment of cooperation they were ultimately joined by a significant number of Republicans in the Senate and a symbolic handful in the House.

“We agreed this would be a truly bipartisan process,” Senator Rob Portman, a Republican from Ohio, told the White House gathering. “This should be the beginning of a renewed effort to work together on big issues facing our country.”

Brutal poll numbers 

The feelgood moment may be hard to sustain.

Biden’s ratings are in a downward spiral, with the latest Washington Post-ABC poll showing just 41 percent approving. Most worrying for the White House, support is ebbing away not just among the crucial independent voters but his own Democratic base.

And despite the reaching out by some Republicans, the bulk of the opposition party is in little mood to declare a truce.

Trump, who is widely expected to seek to return to the White House in the 2024 election, has savaged the 13 Republicans in the House of Representatives who voted alongside the Democrats.

He says Republicans who crossed the aisle should be “ashamed” and are not real Republicans.

Hard-right Republican Representative Marjorie Taylor Greene, an especially vocal Trump booster, called them “traitors.” She tweeted out office phone numbers of the 13 fellow Republicans, some of whom reported getting torrents of violent abuse.

The pressure is also on in the Senate, where Republican leader Mitch McConnell, who voted for the bill, was among the prominent figures keeping away from the South Lawn celebration.

Portman, meanwhile, was freer to make generous comments toward Biden because he has already announced he is not seeking reelection.

With Republicans almost certain to make gains in midterm congressional elections in just under a year, Biden’s already tenuous grip on Washington faces growing strains.

But the White House hopes the bill signing will give Biden, who was due to hold a video-link summit with China’s President Xi Jinping later Monday, new momentum.

Still pending is a $1.75 trillion package for childcare, education and other social spending that Biden says amounts to a historic effort to redress social inequalities.

Again, internal party divisions are holding that up and the proposal has zero Republican support. However, Democratic House Speaker Nancy Pelosi told the White House gathering that “hopefully this week we will be passing” the bill.

After a first 10 months in power dominated by Covid-19 and congressional wrangling, Biden is “frustrated by the negativity and the infighting,” his press secretary, Jen Psaki, told reporters.

However, Biden’s infrastructure sales pitch will aim to change the tune.

Biden will travel Tuesday to New Hampshire to visit a bridge set for infrastructure funding and Detroit on Wednesday to meet union workers. Psaki said “the president wants to spend some sustained time out there communicating.”