Biden Got His Bipartisan Win. Now, Reality Sets In.

WASHINGTON — For more than an hour on Monday, President Biden enjoyed the kind of political moment he had eagerly sought and long promised, surrounded by a bipartisan cast of lawmakers on the South Lawn of the White House for the signing of landmark legislation forged through compromise at both ends of Pennsylvania Avenue.

But after completing the signing ceremony for the $1 trillion infrastructure bill, Mr. Biden returns to a much harsher reality: historically low approval ratings, unified Republican opposition to the centerpiece of his domestic policy, growing alarm in his party about the prospect of losing control of Congress next year and a surprising surge in inflation.

The president and his aides are hoping that the highly choreographed event will begin to allow Mr. Biden to find his footing. They are betting that the bipartisan victory will allow him to project sustained progress in confronting the nation’s problems — not just being different from former President Donald J. Trump.

“I truly believe that 50 years from now, historians are going to look back at this moment and say, That is the moment America began to win the competition for the 21st century,” Mr. Biden said, standing before hundreds of mayors, governors, lawmakers and others with the White House gleaming on a brisk and sunny Washington afternoon behind him.

To chants of “Joe! Joe! Joe!” Mr. Biden called the infrastructure bill “proof that despite the cynics, Democrats and Republicans can come together and deliver results.”

But the president and his top advisers also understand the uncertainty in the country’s deeply polarized electorate, the difficult battles yet to come on Capitol Hill and the often fleeting nature of political victories in the age of 280-character messages on Twitter and vanishing stories on Instagram.

Will Monday’s victory be the steppingstone that Mr. Biden needs for a political turnaround, proving to voters that they got what they expected when they put him in office last year? Or will it be a blip in time, destined to be quickly forgotten among the Washington rancor that is on the way in the days ahead?

“It is a victory in which Biden’s leadership really mattered,” said Matt Bennett, a senior executive for Third Way, a Democratic-leaning group that presses lawmakers in both parties to work together. “That could signal that this is the beginning of a real virtuous circle for him.”

But Mr. Bennett, who attended the signing ceremony, added that the real test for Mr. Biden will be “shaping the public narrative on the enormous benefits of the infrastructure act that is being signed today.”

“That is going to require enormous discipline on the part not only of the president,” he said, “but also congressional Democrats.”

The outcome could help determine the fate of Mr. Biden’s presidency and the course of the Democratic Party as lawmakers prepare to defend their slim majorities in the House and the Senate in next year’s midterm elections.

Senator Rob Portman, Republican of Ohio and one of 10 senators who worked to shape the infrastructure compromise, praised Mr. Biden and Democrats in Congress.

“This is what can happen when Republicans and Democrats decide we’re going to work together to get something done,” said Mr. Portman, who is not running for re-election. (Mr. Biden later called Mr. Portman “a hell of a good guy,” adding that he could only say that without hurting him politically because of the senator’s decision not to seek another term.)

Monday’s signing ceremony was the culmination of a long effort for Mr. Biden. In the Senate, the legislation passed by a lopsided vote of 69 to 30, with even Senator Mitch McConnell, the Republican leader and a chief Biden critic, voting yes. In the House, Mr. Biden wooed a bigger-than-expected group of Republicans to support the effort to repair the nation’s crumbling roads, bridges and airports.

That has been a bipartisan talking point for years; even Mr. Trump repeatedly proclaimed that it was “Infrastructure Week” in Washington, only to see little progress.

“This is a great accomplishment,” Speaker Nancy Pelosi told the crowd on Monday. “And there’s more to come.”

That was clearly the message Mr. Biden wanted to send. His White House staff developed the event with the kind of stagecraft usually reserved for political conventions or campaign events. Flags from each state flapped in the background as Mr. Biden, flanked by Vice President Kamala Harris and a union worker from North Carolina, strode to the lectern as “Hail to the Chief” played.

Now, the challenge for the president is to convince voters that passage of the legislation actually matters to their lives — that it is not just a Washington abstraction, debated in the halls of Congress but with little impact on them.

That effort begins in earnest immediately.

The ceremony on Monday will be followed by a burst of presidential travel aimed at showing the American people real examples of how the new law will pump money into the economy and provide good-paying jobs by upgrading roads, bridges, lead pipes, broadband and other infrastructure.

On Tuesday, Mr. Biden is expected to travel to New Hampshire, where he will speak at a bridge over the Pemigewasset River, which is in critical need of rehabilitation. The next day, he will visit a General Motors electric vehicle assembly plant in Detroit to showcase the billions of dollars to be spent on upgrading electric charging stations around the country.

“Now is an opportunity for the president, the vice president, our cabinet,” Jen Psaki, the White House press secretary, said on Monday, “to be out in the country, connecting the agenda, the impacts on people’s lives, moving beyond the legislative process to talk about how this is going to help them. And we’re hoping that’s going to have an impact.”

History suggests the president and his team have their work cut out for them.

Former President Barack Obama campaigned around the country during his first term in office, telling Americans that the Affordable Care Act would “bend the cost curve” for health insurance and improve coverage. But early glitches in the Obamacare website and opposition from the newly formed Tea Party made the law toxic in many places for many years.

After Mr. Trump passed tax cuts early in his tenure, he hosted a similar celebration (though without the bipartisan sheen) and then failed to sell it to the broader public. Throughout his tenure, the tax cuts remained a largely partisan victory.

During his campaign for president, Mr. Biden promised that he would be able to win the support of Republicans and Democrats for his policies. That message resonated with voters after four years in which Mr. Trump clashed spectacularly with Democrats.

But much of Mr. Biden’s legislation so far has been passed with little support from the opposing party. His $1.9 trillion pandemic relief package was passed in the Senate and the House without any Republican support. And his $1.85 trillion social spending plan, known as Build Back Better, is likely to pass with only Democratic votes.

At home, the president still faces deeply divisive issues such as what to do about the border, clashes about racial sensitivity in schools, prison reform and voting rights. And overseas, Mr. Biden will be confronted with the need to rein in China and Russia, continue to repair relationships with allies and fight terrorism.

In his remarks on Monday, though, Mr. Biden was all smiles.

“As I look out on this crowd today, I see Democrats and Republicans, national leaders, local leaders, all elected officials, labor leaders, businesses,” Mr. Biden said, clearly relishing the moment of victory in a tumultuous year.

“Most of all,” he said, “I see fellow Americans, I see America. Let’s remember this day. Let’s remember we can come together. Most of all, let’s remember what we’ve got done for the American people when we do come together.”