ROME--Nearly five months after President Joe Biden declared “America is back” on his first presidential visit abroad, the president's challenge now that he's back in Europe is convincing the world that America is here to stay.

Attending twin summits in Rome and then Scotland, Biden is asking world leaders to cast their lot with a country that seems unable to agree on its own future.

His visit is set against the backdrop of the ongoing struggle to get his signature domestic agenda through Congress. The president's fellow Democrats have steadily pared back Biden's proposed spending on families, health care and renewable energy to build support for the plan and battled over the tax hikes needed to pay for it.

Because support for the $1.75 trillion package of expanded social programs is unclear, the president's separate $1 trillion infrastructure package is also on hold. This leaves the president to ask the world to judge him based more on his intentions rather than his results.

Biden administration officials contend that American allies understand the messiness of the legislative process and are unfazed, but world leaders also are keenly aware of Biden’s sagging poll numbers, the prospects of a Republican resurgence in Congress in the 2022 midterm election and the specter the presidency could shift to former President Donald Trump or someone with similar politics two years later.

The White House view, laid out by senior administration officials during briefings in Rome, is that American alliances suffered enormous trauma during the last administration and the healing work under Biden is ongoing.

A senior administration official said Saturday the White House believes allies want Biden to lock in as much progress as possible while there is a president who is a deeply committed to transatlantic alliances.

"The administration created really high expectations of a sort of reset in transatlantic ties with the ‘America is back rhetoric,’” said Benjamin Haddad, director of the Europe Center at the Washington think tank Atlantic Council. “I think there was probably too high of expectations that we could just turn the page on the last four years.”

Biden promised that the U.S. would be a more engaged and predictable partner to allies following four years of Donald Trump’s “America First.”

But in the early going of his presidency, he has frustrated allies on the international stage and provided fodder for his Republican critics. Setbacks included the chaotic U.S. withdrawal from Afghanistan and a diplomatic row with France over a plan for the U.S. to equip Australia with nuclear-powered submarines.

Biden also disappointed Eastern European allies, including Poland and Ukraine, over his decision to waive sanctions against German entities involved in the Nord Stream 2 gas pipeline.

The United States has long called the Russia-to-Germany pipeline a threat to European energy security because it increases the continent’s reliance on Russian gas and allows Russia to exert political pressure on its neighbors. Levying sanctions against Germany, however, would have caused a further dispute with one of the United States’ closest allies.

European allies also bristled over the Biden administration restrictions on travel from European Union countries because of the coronavirus pandemic. The administration has announced it will lift the restrictions next month that impact travelers from 33 countries, including members of the EU, China, Iran, South Africa, Brazil, and India.

Some progress was made at the G-20 as the White House announced Saturday the U.S. and European Union had reached an agreement to settle their diplomatic rift over Trump-era steel and aluminum tariffs.

The tariffs were issued on national security grounds and led to retaliatory taxes by the EU. They will not be completely removed. Some European steel and aluminum will enter the U.S. without tariffs and the retaliatory tariffs by the EU will end.

While prospects for what would be the largest-ever U.S. investment in fighting climate change are looking up, the delay in getting there has only reinforced the fickleness of American policy on the eve of the Glasgow summit, underscoring that the priorities of one president can be reversed by the next.

House Democrats hope for a vote on Biden's domestic package, including the climate investment, on Tuesday, when Biden will be winding up his stay at the U.N. climate summit in Glasgow. But it remained unclear whether the ambitious timetable could be met.

If Congress fails to pass legislation for significant action on climate by the United States itself, "it would be like President Trump pulling out of the Paris agreement, again,” U.S. climate envoy and former secretary of state John Kerry told the AP earlier this month.

In a closed-door session with House Democrats that Biden attended just hours before his departure for Rome, House Speaker Nancy Pelosi invoked the president's trip as she tried to rally Democratic votes around the $1 trillion infrastructure package, unsuccessfully attempting to build support for a vote Thursday.

“When the president gets off that plane we want him to have a vote of confidence from this Congress,” she said. She referenced conversations she’s had with world leaders questioning whether American democracy can deliver.

“The rest of the world wonders whether we can function,” Biden told the lawmakers, according to a source familiar with his remarks.

Biden is trying to prove it can with his actions at the Group of 20 summit in Rome and next at the U.N. climate summit in Glasgow.

On Saturday, he huddled in Rome with Germany’s Angela Merkel, France’s Emmanuel Macron, and Britain’s Boris Johnson to coordinate strategy on the Iran deal. The four-way meeting was meant as a study in contrast from the Trump administration, when the Iran nuclear issue marked one of the major flashpoints between the U.S. and Europe.

Biden also met individually with Macron on Friday, part of an attempt to move past a separate row over a secret U.S.-U.K. deal to sell nuclear-powered submarines to Australia that cost France tens of billions of dollars by ending its own planned submarine sale to the ally.

“For me, this is very much the beginning of a process of trust, of confidence, which we’re building together,” Macron told Biden.

William Howell, a University of Chicago political scientist, said Biden’s challenge says less about his skills or domestic political support for his agenda and more about the contemporary state of American politics.

“The pervasive gridlock, polarization, and distrust that characterize our national politics will ... give foreign leaders some pause before entering into long-term, costly agreements with us,” Howell said.

The president did secure a global agreement to establish a global minimum tax for corporations, a long-sought move designed to prevent companies from moving profits to offshore tax havens. But the legislation implementing it in the U.S. is part of the broader package of legislation that hasn't yet passed Congress.