Last month, Japan and South Korea announced a historic agreement that’s supposed to “finally and irreversibly” settle grievances about the sexual enslavement of Korean women in Japanese military brothels before and during World War II. Both governments hope they’ve resolved what Korean President Park Geun-hye called “the biggest obstacle” in bilateral relations, and can move on.

That’s highly unlikely, as my research suggests. The survivors and their backers have spent decades creating a powerful movement for redress — and the latest deal falls far short of their goals.

What Japan and Korea agreed to

In the agreement, Japan apologized and offered 1 billion yen (about $8.5 million) in taxpayer money to support the 46 surviving comfort women through a foundation run by the Korean government. Japan and Korea also pledged to cooperate on unspecified “programs to restore the honor and dignity and to heal the psychological wounds” of the former sex slaves.

The Japanese government has gotten a commitment that neither state will criticize the other on the issue, including at the United Nations. They’ve also won an acknowledgment from the Korean government of the Japanese government’s concerns about a statue of a young girl that has become a symbol of the global movement to address wartime sexual slavery; in 2011, civic groups installed the statue opposite the gates of the Japanese Embassy in Seoul. The Korean government agreed to discuss this statue with activists.

Both governments urgently want to put the so-called comfort women issue behind them so they can restore political and economic ties. As Jennifer Lind notes, Japan has a strategic need to cooperate more closely with Korea and the United States to cope with the threat from China, which may help Japanese conservatives stomach the prime minister’s apology. Park pushed for a deal for the aging survivors in 2015, the 50th anniversary of normalized Japan-Korea ties and 70th anniversary of the end of the war.

How did powerless former sex slaves make this happen?

Activism by and on behalf of the former sex slaves helped turn this issue into the main sticking point between two neighboring democracies with many other shared interests. The former sex slaves retain considerable support from other social groups and the public, which will make implementing the accord difficult.

In my forthcoming book, “Accidental Activists,” I look at six groups of Japanese and Korean people who mobilized to hold their own government accountable for more recent wrongs or negligent policies. This research helps explain how initially powerless groups — like the Korean comfort women — can gain such support and political influence.

Former Korean sex slaves began their campaign as powerless outsiders. As Sarah Soh and Kathy Moon have documented, Korea’s conservative, masculine culture helped silence many women who had been forced into sexual labor in World War II, reinforcing their isolation and stigmatization. Korean dictators also made it hard for most groups to organize and speak in public. And Japan denied wrongdoing.

However, Korean comfort women started to speak out in the early 1990s after Korea democratized and the Showa Emperor of Japan died. Supported by Korean and Japanese feminists and scholars, they filed lawsuits for reparations in Japanese, U.S. and Korean courts. They mostly lost. But a Japanese court issued a ruling (later overturned) in their favor in 1998. Korea’s Constitutional Court ruled in 2011 that the Korean government’s failure to resolve the issue violated the constitution. In 1992, the movement began holding weekly Wednesday demonstrations in front of the Japanese Embassy in Seoul. The women’s moral legitimacy kept increasing as they gained public support and media attention. More important, the movement’s account of Japanese wrongdoing became widely accepted in Korea. The movement has persuaded Korean policymakers that most voters agree with their demands.

They also took their cause to the international stage, at the United Nations and elsewhere, convincing the U.S. House of Representatives, former secretary of state Hillary Clinton and political elites in other countries to ask Japan to address the claims of surviving sex slaves of Korean and other nationalities. Ethnically Korean groups in the United States and elsewhere expanded the campaign’s grass-roots support.

This kind of mobilization is difficult and risky — but when it works, political leaders feel vulnerable unless they respond to victims’ demands.

Korean civic groups are far less interested in settling this than their government

The governments negotiated without the victims and their supporters there. Presumably that made negotiations easier. But that exclusion will make it harder for the Korean government to implement the deal, because the movement rejects the agreement.

Among other things, the women were angry that the Korean government didn’t consult the survivors during the negotiations. They had hoped Seoul would press for official reparations, with Japan acknowledging both moral and legal responsibility for their enslavement. They and their supporters object to moving the statue and have held vigils to protect it. Editorials in left-leaning news outlets echo the survivors, calling the agreement “humiliating.”

And so the Wednesday demonstrations — now in their 24th year — have been drawing hundreds more attendees than usual and inspiring similar rallies around Korea and abroad. A group of nearly 400 scholars and activists has criticized the accord as a diplomatic mistake. The main opposition party, the Minjoo Party of Korea, has submitted a resolution in the National Assembly calling for the bilateral accord’s nullification.

These feelings are echoed by the Korean public. A recent Gallup Korea poll found that 54 percent of Koreans disapprove of the deal — mainly because the governments had excluded the survivors — and just 26 percent approve of the accord. According to JoongAng Ilbo, a conservative major daily, 58.2 percent of Koreans do not believe the accord has “finally and irreversibly” resolved the issue, and more than three quarters of respondents question the sincerity of Abe’s apology.

Predictably, attitudes split along party and generational lines. More than three-quarters of the ruling Saenuri Party’s supporters approve of the agreement. But just 8.5 percent of Minjoo Party of Korea supporters do. Younger people are also less positive about the deal, just as they are about Park’s administration. Two-thirds of Korean respondents of all ages opposed moving the statue; that rises to 86.8 percent of those in their 20s.

The South Korean government needs the movement’s support to move ahead with the agreement

The Korean government has repeatedly defended the agreement and appealed for cooperation. But it can’t move ahead without the women and their supporting organizations. Without them, how can it establish a foundation that can receive funds from Japan? Japanese media have reported rumors that the Japanese government will not deliver the funds if the statue is not moved. Though Seoul denies these rumors, it’s not at all clear that the Korean government will be able to persuade the survivors and their backers to join its agreement.

The former sex slaves’ movement still has the broad political support that brought these two governments to the table. And the movement’s political leverage did not disappear with the agreement announced last week. It has the power to refuse to go along.

Which means this “final and irreversible” resolution may be nothing of the sort.

Celeste Arrington is Korea Foundation assistant professor of political science and international affairs at the George Washington University. Her book, “Accidental Activists: Victim Movements and Government Accountability in Japan and South Korea,” will be published by Cornell University Press in March.