Visiting Japan to show solidarity with one of the United States’ oldest allies, Vice President Biden got a glimpse Tuesday of the rapid disaster recovery taking place in the northeast as well as the political disarray in Tokyo that threatens to hold it back.

In a speech at the airport in Sendai, the nearest large city to the March 11 earthquake and tsunami, Biden described Japan as the “anchor” of U.S. interests in Asia and expressed awe at the “legendary industriousness” of its rebuilding effort. He also met with Prime Minister Naoto Kan, who, according to reports in Tokyo, apologized for “Japan’s political situation” — a state of affairs that will become even more uncertain next week when Kan resigns.

The much-criticized Kan probably will step down next Tuesday, Economics Minister Kaoru Yosano said after an informal cabinet meeting. The ruling Democratic Party of Japan is expected to vote Monday on its next leader. The winner, who will become Japan’s seventh prime minister in five years, will inherit the same locked parliament and disaster-response challenges that have stymied Kan.

Biden met with Kan in the prime minister’s office Tuesday morning on the final stop of an eight-day Asia trip that included visits to China and Mongolia. Kan had been scheduled to travel to Washington next month, but the trip was called off as his grip on his post unraveled.

“I make the point that while you’re struggling to deal with one of the greatest natural disasters any country has faced, we are dealing with getting our budget in order,” Biden told Kan. “There are voices in the world who are counting us out. They’re making a very bad bet.”

At the Sendai airport, which had been flooded by the tsunami, Biden emphasized the United States’ commitment to helping Japan recover. Following the 9.0-magnitude earthquake and the resulting wave, hundreds of people took refuge on the airport’s roof. Restoring the runway became a focal point of the U.S. military’s humanitarian effort — dubbed “Operation Tomodachi,” or Operation Friend — and the airport reopened for emergency-supply takeoffs and landings within a week.

Even five months after the disaster, hills of rubble bulge on the airport property. A graveyard of smashed cars sits just down the road. After his speech, Biden toured the low-lying disaster zone near the mouth of the Natori River. He laid a bouquet on a pile of stones in front of a destroyed home and met with evacuees at a community center. Some told him they had spent days at the airport while the outskirts of their city lay underwater.

“The Americans looked at that tsunami and could not imagine — could not imagine — how anybody could do it,” Biden told several evacuees in a parking lot outside the community center. “They also saw the resolve and courage of the Japanese people. The way they helped people. They way they came together. It was the envy of the world.”

Biden had questions for those who had lost their homes. Were their family members killed? Will they rebuild in the same neighborhoods? Is the government compensating them?

The last question prompted one resident to explain that the central government has not yet passed a third supplementary budget for fiscal 2011, intended to fund further disaster relief.

Observers say they hope that budget will be passed by the end of September, under a new prime minister. On Tuesday, former foreign minister Seiji Maehara, a favorite in many polls to succeed Kan, declared his candidacy for the job. Other front-runners include Finance Minister Yoshihiko Noda and Industry Minister Banri Kaieda.

Special correspondent Ayako Mie in Tokyo contributed to this report.