U.S. Allies Watch the Debate With Shaking Heads and a Question: What Now?

During Thursday night’s debate, President Biden told former President Donald J. Trump that the United States is the “envy of the world.”

After watching their performance, many of America’s friends might beg to differ.

In Europe and Asia, the back-and-forth between the blustering Mr. Trump and the faltering Mr. Biden set analysts fretting — and not just about who might win the election in November.

“That whole thing was an unmitigated disaster,” Simon Canning, a communications manager in Australia, wrote on social media. “A total shambles, from both the candidates and the moderators. America is in very, very deep trouble.”

Sergey Radchenko, a historian at the Johns Hopkins School of Advanced International Studies in Washington, posted, “This election is doing more to discredit American democracy than Vladimir Putin and Xi Jinping could ever hope to,” referring to the presidents of Russia and China, America’s most powerful rivals for global leadership.

“I am worried about the image projected to the outside world,” he continued. “It is not an image of leadership. It is an image of terminal decline.”

Whoever becomes president, the United States faces major global challenges — in Asia, from a rising China and a nuclear North Korea recently bolstered by Mr. Putin; in Europe from Russia’s war against Ukraine; and in the Middle East, where Israel’s war against Hamas threatens to escalate to southern Lebanon and even Iran.