TOKYO — President Biden has vowed to rally the United States' partners to respond to Myanmar's military coup. But persuading Asian allies to support sanctions or moves to isolate the regime will be no easy task, given extensive business interests, a genuine belief in engagement and a desire not to cede strategic ground to China.

The implication, experts said, is that if Myanmar’s generals thought they could manage the diplomatic and economic fallout from their ouster on Monday of the civilian-led government of Aung San Suu Kyi, they were probably right. On Thursday, faced with domestic resistance to its power grab, the military regime blocked Facebook and other messaging apps.

“It’s almost 100 percent certain that none of Myanmar’s main economic partners in Asia — Japan, South Korea, Singapore, Thailand and, of course, not China — would join the U.S. and the [European Union] if they were to impose sanctions on or cut off economic aid to Myanmar,” said Murray Hiebert, a senior associate in the Southeast Asia program at the Center for Strategic and International Studies.

In threatening new economic sanctions this week, Biden warned that the United States was “taking note of those who stand with the people of Myanmar at this difficult hour.”

But in Asia, there is a sense that two decades of sanctions in the 1990s and 2000s during Myanmar’s earlier period of military rule simply pushed the junta closer to China, while ordinary people languished in poverty.

This calculation limits Biden’s options.

“Sanctions will help make the U.S. feel better psychologically about having whacked the generals, but it won’t mean much in economic terms if America’s friends and allies in Asia keep working with the junta,” Hiebert said.

Japan is a key player. The most important American ally in Asia also prides itself on its close historical ties to Myanmar. Tokyo did not join international sanctions during Myanmar’s previous period of military rule and would not support sweeping sanctions now, experts said.

Economic ties boomed after Myanmar began a transition to quasi-democratic rule last decade. More than 400 Japanese companies do business in the country, according to the Japan External Trade Organization, an eightfold increase since 2011, making products such as cars and beer.

Japan is a major aid donor and Myanmar’s fourth-largest trading partner behind China, Thailand and Singapore, as well as the fourth-largest direct investor in the past five years behind Singapore, China and Hong Kong, U.N. and Myanmar government data show.

Prime Minister Yoshihide Suga has been criticized for being slow to respond to the coup, but Foreign Minister Toshimitsu Motegi expressed “grave concern” and signed on to a statement from the Group of Seven leading industrialized nations.

“The Japanese government is very disappointed with the coup,” said Nobuyoshi Nishizawa, a professor at the University of East Asia in Shimonoseki. “But Japan will not want to ruin its friendly relationship with Myanmar, so they will only make a soft response.”

An early indication came when Deputy Defense Minister Yasuhide Nakayama told Reuters it was important to maintain communication with Myanmar’s generals and warned against suspending Japan’s partnership program with the military.

“If we do not approach this well, Myanmar could grow further away from politically free democratic nations and join the league of China,” he said. “I think that would pose a risk to the security of the region.”

Toshihiro Kudo, a professor at the National Graduate Institute for Policy Studies in Tokyo who specializes in Southeast Asia, argues that Japanese investment and aid have helped ordinary people.

“Unlike 10 years ago, Myanmar is integrated into the supply chain in the region,” he said. “And people don’t want to sacrifice their economic opportunities.”

While the Association of Southeast Asian Nations is unlikely to take a firm stance against the coup, Washington will probably look for more from another ally, South Korea, the sixth-largest direct investor in Myanmar. If so, it may be disappointed.

“South Korea, because of its sizable investment in Myanmar, cannot afford to take a firm stance on the tensions there,” said Kim Sung-won, a Myanmar expert at Busan University of Foreign Studies in South Korea. “Seoul is walking on eggshells while observing whether Washington ramps up pressure on Myanmar.”

While the South Korean Foreign Ministry has expressed “deep concern” at events in Myanmar, former U.N.-appointed expert on Myanmar Lee Yang-hee took issue with South Korea’s “unprincipled and questionable investments” in the country in a tweet on Wednesday and urged Seoul to “speak out against the coup d’etat.”

Japan was also criticized for abstaining from a 2019 vote at the U.N. Human Rights Council condemning the Myanmar military’s atrocities against the Rohingya minority. Companies such as beermaker Kirin and Hotel Okura have been criticized by rights activists for their joint ventures with companies controlled by Myanmar’s military. On Friday, Kirin said it would end its joint venture with Myanma Economic Holdings, a military-run conglomerate, in light of “the recent actions of the military.”

America’s own insistence on democracy abroad has always been very selective — oil supplies or anti-Communist credentials have given many regimes a free hand, and its own moral high ground has not been enhanced by events surrounding its own contested presidential election.

Nevertheless, Phil Robertson, deputy Asia director at Human Rights Watch, said he hopes that public pressure could spur Tokyo into action.

That would mean not only speaking out forcefully against the coup, but joining targeted actions against top military leaders. He suggested asset freezes, travel bans and pushing for a global arms embargo on the regime.

Diplomatically, Tokyo has enough sway to make a difference, Robertson argued.

“There is a long relationship there that is absolutely critical,” he said. “If Japan in fact says to the Myanmar military, ‘Look, guys, you are wrong. We are not going to support you,’ that is something that will resonate.”

But few believe that’s going to happen.

“It is easy to talk about a values-based approach, but when you are confronted with this coup, it exposes that as empty rhetoric,” said Daniel Sneider, an East Asia specialist at Stanford University, referring to Japan’s regional strategy that emphasizes free trade along with democracy and human rights.

Indeed, Myanmar’s generals would have known that when they seized power this week.

“They knew there would be consequences, but I think they calculated, of course taking China into account, that they could manage the international impact,” Kudo said.

Min Joo Kim in Seoul and Julia Mio Inuma in Tokyo contributed to this report.