WASHINGTON — President Joe Biden welcomes German Chancellor Angela Merkel to the White House for what is likely to be her last official visit and one to which she's bringing a bag full of issues and an overarching message for Berlin's close ally: You've got a friend.

The veteran German leader is expected Thursday to discuss the coronavirus pandemic, the rise of China and a Russian gas pipeline that Washington opposes. She will meet with Biden, Vice President Kamala Harris and other senior U.S. officials.

"In part, this is a farewell visit. In part, she is signaling continuity and stability in the German-U.S. relationship," said Johannes Thimm, a senior fellow at the German Institute for International and Security Affairs, a think tank in Berlin.

After 16 years of dealing with Merkel, many officials in Washington and elsewhere are wondering what course Germany might take after the next election. The longtime chancellor — who has dealt with four U.S. presidents in her time — will seek to reassure them that there won't be a huge shift, Thimm said.

Merkel's party is leading in polls ahead of Germany's Sept. 26 election, but the environmentalist Greens and the center-left Social Democrats are also vying to lead a future government. While the three parties differ in many policy areas, all are committed to a strong trans-Atlantic relationship.

One sour note that preceded and outlasted the Trump era of diplomatic discord with Washington has been the thorny issue of a new pipeline taking natural gas from Russia to Germany.

The United States has long argued that the Nord Stream 2 project threatens European energy security and harms allies in Eastern Europe. But Biden recently waived looming sanctions against German entities involved in the project. The move angered many Democratic and Republican lawmakers.

Biden is expected to raise his concerns about the pipeline project when the two leaders speak privately, but the White House was not anticipating any sort of formal announcement to come out of the leaders' talk, according to a senior Biden administration official who briefed reporters ahead of the chancellor's visit.

Merkel sought this week to dampen expectations for an imminent breakthrough, but she is likely to want to resolve the issue before leaving office. "It weighs on German-U.S. relations and German-EU relations," Thimm said.

While German officials have been unusually coy about which topics will be discussed during the trip, Merkel's spokesperson confirmed Wednesday that China will come up.

"That can be said with relative certainty," Steffen Seibert told reporters. "This also played an important role at the G-7 summit, where the chancellor and the American president last met."

Germany has strong trade ties with China but has also been critical of Beijing's human rights record. Merkel is keen to avoid a situation in which Germany, or the European Union, might be forced to choose sides between China and the United States.

Merkel has insisted on the need to cooperate with China on global issues such as combating climate change and tackling the coronavirus pandemic, even while Biden's predecessor Donald Trump was accusing Beijing of having started it.

The humanitarian group Doctors Without Borders urged Biden on Wednesday to lean on Merkel to drop her opposition to proposals for suspending vaccine patents. Merkel, a trained scientist, has argued that lifting the patents wouldn't be effective and could harm future research and development efforts. 

Ahead of her visit, a group of Democratic lawmakers this week called on Germany to drop its "blockade" of a COVID-19-related waiver of intellectual property rights under global trade rules. Such a waiver, the lawmakers argued, would help scale production of effective vaccines around the world.

The Biden administration has expressed support for the waiver being discussed at the World Trade Organization, but White House officials do not anticipate differences being resolved during Merkel's visit. 

And while there are points of tension, Biden seems eager to offer Merkel a proper farewell. Harris will host Merkel for a working breakfast at her residence on the grounds of the U.S. Naval Observatory. After afternoon meetings with Biden and his team at the White House and a joint news conference, the president plans to host a small dinner in honor of Merkel and her husband, chemist Joachim Sauer.

Merkel will also receive an honorary doctorate, her 18th, from Johns Hopkins University and is scheduled to speak at the university's School of Advanced International Studies.

Merkel's trip may not be her last, either. The 66-year-old said that growing up in East Germany she dreamed of being able to travel to America on her retirement, when the communist bloc tended to relax some of the restrictions on its citizens. 

So far, Merkel has announced no plans for her time after office.