Mr. Biden, a veteran of half a century in high office in Washington, has regularly remarked on the uncertainty surrounding America’s place in the world that he discovered when he took office after Mr. Trump’s disruptive four years. “America is back,” he said he would tell foreign counterparts, only to hear, “But for how long?”

By contrast to his predecessor, Mr. Biden has conducted a far more conventional foreign policy familiar to world leaders, and foreign officials see him as a more traditional U.S. president. But they also understand that he is presiding over a country whose democracy has been tested and found to be fragile. And they see a fractious politics in Washington that values confrontation over compromise, even at the risk of something that would have once been unimaginable, like a default.

“For sure, the U.S. debt ceiling issue will be a topic of conversation and concern at the G7 summit,” Matthew P. Goodman, a senior vice president for economics at the Center for Strategic and International Studies in Washington, said at a briefing about the meeting last week. “I’m sure the other leaders will ask, you know, how serious this risk is. And I assume President Biden will say he’s working on it and doing everything he can to avoid it.”

By this point, U.S. partners have become oddly accustomed to the culture that dominates Washington. They have watched the brewing debt ceiling fight with little evident fear.

“I don’t think many European governments are very concerned, presumably because these crises come round quite often but never end in disaster,” said Charles Grant, the director of the Centre for European Reform in London. “Cutting short the trip is a bad signal, but there is such good will to Biden in most capitals that they are prepared to cut him some slack.”