As President Joe Biden jets off to Europe to meet with allies, some of the United States' closest partners are still wondering if America is truly "back" as Biden proclaimed earlier this year.
Cautious about Biden's domestic standing, and smarting from his lack of coordination on the withdrawal from Afghanistan, they are concerned whether his presidency truly represents a break from the isolationist, confrontational foreign policies of his predecessor, President Donald Trump, according to U.S. foreign policy experts.
Biden's second trip abroad as president will take him to Rome and Scotland, where he'll attend international summits aimed at tackling the coronavirus pandemic, global finance and the climate crisis.
But the excitement over Biden's arrival on the world stage has belied the fact that he's continued some key Trump policies, such as tariffs on China and a general pivot -- started under President Barack Obama -- toward Asia and the Pacific. Congressional inaction on fighting climate change also has the potential to weaken Biden's hand.
"I think there was probably too high expectation that we could just turn the page of the last four years, or maybe we attributed to Trump some policies that were more structural, such as the U.S. shift to China and to the Indo-Pacific," Benjamin Haddad, the senior director of the Europe Center at the Atlantic Council, told ABC News.
When the president took to the world stage for his first trip abroad, with a June trip to the United Kingdom, Belgium and Switzerland, he and other world leaders celebrated the United States' changed tone.
Biden preached multilateralism, which Trump had maligned for four years. And European allies rejoiced.
When Macron met the U.S. president during a summit in England, the French leader told reporters that he "definitely" believed "America is back."
"I think it's great," Macron said, "to have the U.S. president part of the club and very willing to cooperate."
But French-U.S. relations hit a major snag last month when the Biden administration announced it would sell Australia nuclear submarines -- resulting in Australia canceling a major defense deal with France.
France recalled its ambassador from Washington in response to the so-called "sub snub," and its foreign minister compared Biden's style to Trump's.
But since then, Biden and Macron have sought to repair ties: They held a phone call last week, have launched meetings between senior officials from both countries, and on Friday, plan to meet in Rome. Vice President Kamala Harris will travel to Paris next month, too, according to her office.
"In many ways, this is not just about the French," Célia Belin, an expert on trans-Atlantic relations at the Brookings Institution, told ABC News. "It goes to the core of the conversation that the U.S. should be having with their allies, which is, what do you actually expect from European allies in the Indo-Pacific?"
Before those major hiccups, Biden's reception in Europe stood in stark contrast with the constant spats -- both personal and policy-wise -- between U.S. allies and Trump.
Calling his foreign policy "America First," Trump actively sought to lessen American commitments abroad.
He pulled the United States out of international organizations and treaties and publicly called on allies to pay more for defense. His fights with foreign leaders marred the international summits he did attend.
Biden campaigned in large part on reversing the damage he said Trump had caused, and when he won the presidency, U.S. allies rattled by years of instability from Washington had high hopes of a return to the pre-Trump years.
"The decisions that the administration has taken, very much and consistent with the domestic mood and polarization, have left them quite disappointed," Heather Conley, the director of the Europe, Russia and Eurasia program at the Center for Strategic and International Studies, said.
Allies are now facing the decision of whether to work independently of the United States on certain issues, uncertain whether Biden's young administration will truly restore America's relationship with the world, Conley said.
"I think the question for me is, moving forward, has the administration understood that these decisions have profoundly challenged and questioned our allies as far as our credibility?" she said. "Can we restore that trust?"
Biden planned to arrive in Rome late Thursday ahead of a Friday meeting with Macron, and another meeting with Pope Francis at the Vatican.
In the Italian capital, the president also planned to attend a summit of the leaders of rich and developing nations known as the Group of 20, or G-20, where he plans to formalize an international agreement on a 15% minimum tax for corporations. The global response to the coronavirus pandemic and other global finance issues are also expected to take center stage.
Biden then plans to travel to Glasgow, Scotland, where on Monday and Tuesday, he is scheduled to attend the U.N. climate change conference known as COP26. The U.S. is pushing countries to cement emissions-reduction targets they had set as part of the 2015 Paris climate agreement.
He won't have the opportunity to meet in person with two leaders who play a key role on climate and security issues: Chinese President Xi Jinping and Russian President Vladimir Putin. They plan to attend the summits virtually, citing the COVID-19 situation in their countries.
Biden had hoped to travel abroad with two major pieces of legislation in his pocket: his bipartisan $1 trillion physical infrastructure bill, which has already passed the Senate, and his larger social package -- which he calls the "Build Back Better" bill and is full of Democratic priorities like universal pre-kindergarten, expanded healthcare, guaranteed paid leave and programs to combat the climate crisis.
Strong climate provisions, in particular, could lend him credibility at COP26, showing the United States put its money where its mouth is as it hectors developing nations to commit to lowering emissions -- and others to fulfill their pledges.
A recent report by the New York-based research institute Rhodium Group -- frequently cited by the White House -- found that the only way the U.S. could meet its goal of halving its 2005 emissions levels by 2030 would be with congressional action. Experts have questioned whether the climate provisions in the "Build Back Better" bill will have enough teeth to help the U.S. meet that target.
"I'm presenting a commitment to the world that we will, in fact, get to net zero emissions on electric power by 2035 and net zero emissions across the board by 2050 or before," Biden said last week during a town hall hosted by CNN, referencing COP26. "But we have to do so much between now and 2030 to demonstrate what we're going to -- that we're going to do."
Twin legislative victories would also show allies that Biden had political strength and could push through the policies he champions when abroad. They could also help him with sagging poll numbers at home.
"For messaging purposes, it's nice to have a win when you're abroad that you can brag about a little bit," Amanda Rothschild, who served as a speechwriter on the Trump White House's National Security Council, told ABC News.
The president had made clear that he wanted his $1 trillion physical infrastructure deal to pass Congress by the time he departed, and that he also wanted a deal on his larger social bill -- which is expected to contain massive climate-related investments.
When it became clear in recent days that might not be possible in time for the trip, the White House has emphasized, instead, that Democratic lawmakers' negotiations seem to be coming to a conclusion soon.
Biden's top national security adviser, Jake Sullivan, told reporters Tuesday that U.S. allies are "excited" about the investments the president is pursuing in climate change, clean energy, infrastructure, and domestic economic growth.
"They want to see the United States making these investments," Sullivan said. "They also recognize that the United States has a set of democratic institutions, has a Congress; that this is a process; that it needs to be worked through."
Sullivan, though, said world leaders understood the ups and downs of policy-making.
"I think you've got a sophisticated set of world leaders," he said, "who understand politics in their own country, and understand American democracy, and recognize that working through a complex, far-reaching negotiation on some of the largest investments in modern memory in the United States -- that that takes time."
Haddad, of the Atlantic Council, said European allies were less interested in the nitty gritty of legislating and more on practical matters like Republicans blocking the confirmation of most of Biden's ambassadorial nominees.
"I don't think the day-to-day negotiations in Congress are really being noticed in Europe," Haddad said. "But the domestic political paralysis does have an impact on U.S. leadership."
But if Biden arrives in Europe without those pieces of legislation in hand, "it’s going to be much harder for him to make the case, you know, the U.S. is back," Matthew Goodman, an expert on international economic policy at the Center for Strategic and International Studies, said.
Still, Biden's not Trump -- and even if allies are nervous, the fledgling administration still has time to gain its footing on the international front, after spending much of its time focused on the domestic economic recovery, according to Goodman, who served in the White House and State Department under President Barack Obama.
"I think the rest of the world is going to be relieved that, you know, it’s not Donald Trump at the table, frankly," Goodman, who served in the Obama administration, said. "He was considered a very disruptive force, and so I think, by comparison, Biden’s going to be well received in that sense."