President Joe Biden will celebrate America's defeat of Covid-19 with a July 4th barbecue this Sunday, but the fireworks smoke will barely clear before the Democrat has to confront maybe even tougher challenges.

About 1,000 guests -- emergency service and essential workers, military members and their families -- are set to pour into the White House grounds for the kind of party unimaginable a year ago, when the country was under lockdown.

The Independence Day bash on the South Lawn, followed by a thunderous fireworks display on the National Mall, will allow Biden to mark what he's calling "independence from this virus."

Biden's To Do list features a staggering number of crises and headaches, ranging from climate change to handling a desperately divided Congress and a vengeful Donald Trump.

At least for one humid Washington evening, though, the 78-year-old Biden will be able to kick back and celebrate.

After leading the world in Covid deaths -- more than 600,000 -- the United States has emerged as a model for getting the novel coronavirus under control and the economy back on track.

Much of that is down to Biden reversing Trump's chaotic response with a focused campaign to encourage mask wearing and vaccinations.

He also got Congress to approve a historic $1.9 trillion American Rescue Plan, super-charging economic recovery and protecting the most vulnerable.

There are however some hefty wrinkles.

Biden's much-promoted goal of having 70 percent of US adults receive at least one dose of vaccine by July 4 will narrowly miss.

And celebratory White House statements tend to dodge emerging threats from the highly contagious Delta variant.

"If you've been vaccinated, the message we're conveying is you're safe," was press secretary Jen Psaki's response, when asked about the wisdom of staging a South Lawn party.

Now the hard part?

But the global pandemic wasn't the only unprecedented test for Biden on January 20, when he became the oldest president to take office in US history.

"He faced really the most daunting challenge of an incoming first term president since Franklin Roosevelt in 1933" during the Great Depression, said American University history professor Allan Lichtman.

Biden "had an economic crisis, he had a still raging pandemic on his hands -- you've never quite had that kind of combination."

That was before throwing in an ex-president disputing the election result, a razor-thin congressional majority, an explosive racial divide, the perilous withdrawal from Afghanistan, and international tensions stretching from China to Russia.

Covid and economic rescue were "probably the least daunting of the tasks," Lichtman said.

Sunny figure

Despite all that, Biden's genteel manners and pleas for unity stand out in a town inundated during the Trump years by partisan fighting, impeachments, and startling breaches of presidential decorum.

The veteran politician in aviator sunglasses epitomizes the Washington archetype of the "happy warrior."

From now on, though, he'll have his work cut out to keep smiling.

With Republicans looking to take over Congress in November 2022 midterm elections, and opponents like Florida Governor Ron DeSantis -- not to mention Trump -- exploring 2024 presidential challenges, storm clouds are thickening.

Biden's immediate battle is with both Republicans and the left of his Democratic party on a giant infrastructure spending package.

Win there this summer and Biden may get political capital for even more, like voting rights protection, police reforms and other key planks of his platform.

Fail on infrastructure, however, and the Biden balloon could deflate.

And while the strengthening economy is a huge plus, inflation is an increasing politically damaging worry.

A cute White House press release Thursday about the "Hot Dog" economy -- graphics showed price drops for July 4th lemonade, hamburger meat and ice cream -- is unlikely to persuade many.

The government's "core personal consumption" price index rose 3.4 percent in May, compared to last year, the steepest increase since 1992.

The White House -- at least outwardly -- continues to brim with confidence.

June polls showed a dip in support for Biden, yet he retains approval ratings solidly over 50 percent, something Trump never achieved.

He's also making new ground. A Yahoo News/YouGov poll in June showed six in 10 Republicans support a $1.2 trillion version of the infrastructure spending proposals.

Numbers like these appear to be fueling Biden's ultimate bet: that Americans are hungry for big solutions -- as big as the mountainous problems facing their country.

Writing about that infrastructure plan on Yahoo! this week, Biden said the real issue was about so much more than roads and bridges.

"It is a signal to ourselves, and to the world," he said. "That American democracy can work and deliver for the people."