Abe Shinzo, Japan’s longest-serving and most consequential prime minister in decades, has resigned from his post over health complications.

After weeks of speculation fueled by recent hospital visits, Abe made official what many suspected: Though his chronic ulcerative colitis is not life-threatening, he is just too sick to govern.

“I don’t want to make mistakes in important political decisions” as he deals with a worsening bout of the bowel disease, he told reporters on Friday. “I decided I shouldn’t continue sitting in this seat as long as I cannot respond to the mandate of the people with confidence.”

Abe will stay in the role he assumed for a second time in 2012 (he resigned after only one year in charge in 2007, also because of his health), but will step aside once his conservative Liberal Democratic Party picks a new leader to helm the party. That choice will likely occur by the end of September. He’ll remain a member of the parliament’s lower house afterward and a key party member.

He did not name a favorite to succeed him, opening up a political scramble to lead the world’s third-largest economy — and potentially carry on his legacy.

The 65-year-old’s resignation is a stunning development with profound implications for the country, East Asia, and US foreign policy toward the region.

An avowed nationalist, Abe came into office eight years ago making two big promises.

The first was to jump-start Japan’s long sputtering economy — and his record on that was mixed. Japan’s economy didn’t skyrocket under his leadership, but overall it grew modestly after two preceding decades of deflation. And it recently entered a coronavirus-induced recession.

Still, he made some pretty remarkable reforms, such as allowing foreign workers into the country for five-year periods, championing major stimulus investments and changes to monetary policy, reforming the nation’s tourist industry, and making it easier — although still far from easy — for women to work outside the home by expanding kindergarten and home care.

But the recent hit to the economy, exacerbated by the nation’s coronavirus outbreak Abe failed to fully control, plunged his approval ratings into the 30s. That may have contributed to his decision to cede control now.

His second promise was much more visible to the world and controversial: Japan would pursue a muscular foreign policy with a special focus on countering China — a major break from Tokyo’s ways in the post-war era.

“I’ve realized that Japan is expected to exert leadership not just on the economic front, but also in the field of security in the Asia-Pacific,” he told the Wall Street Journal in October 2013, just 10 months after taking office. “There are concerns that China is attempting to change the status quo by force, rather than by rule of law,” he continued, adding that “it shouldn’t take that path, and many nations expect Japan to strongly express that view.”

Many Japanese allies approved of that more aggressive Japanese stance. “Abe set Japan on a grand strategy to secure a free and open Indo-Pacific that was embraced by the United States, India, and Australia and welcomed by much of South and Southeast Asia and Europe,” said Mike Green, a Japan expert at the Center for Strategic and International Studies think tank in Washington.

Such a policy required Japan to have a very close relationship with the United States, which Abe pursued and cultivated throughout his time in power. For example, he was the first foreign leader to visit President-elect Donald Trump in November 2016, spending about 90 minutes with him in Trump Tower. Those advances didn’t always work, though, as Trump berated Japan over trade issues and for not paying more to host the roughly 50,000 US troops in the country.

He had other global failures, too. He didn’t complete a major effort to revise Japan’s US-created pacifist constitution to allow for a more traditional military banned since World War II, didn’t reach deals with Russia or China over long-disputed islands, exacerbated tensions with South Korea, and failed to curb North Korea’s nuclear program alongside allies.