Liulin Wei, left, a medical school graduate whose short post on a Taiwanese web portal sparked a movement now known as the “White Shirt Army,” meets with another follower in Taipei, Taiwan. (William Wan/The Washington Post)

For decades this island has been bitterly divided into blue and green, the colors of its rival political parties. But that two-toned dichotomy has been upset in recent months by a sea of youths dressed in white.

Now known as the “White Shirt Army,” the young people have become the biggest, most surprising social movement in Taiwan’s recent history. Some experts believe their emergence represents a shift in the political thinking and direction of the country.

“We don’t support any side or leader,” said Liulin Wei, a lanky, soft-spoken 30-year-old who sparked the movement with a short online post four months ago. “We are for civil rights, common values, democracy. And we made it very simple to join. You just put on a white shirt.”

The group’s emphasis on civil-society issues comes after decades in which Taiwanese politics have been dominated by the existential question of independence from mainland China. While China considers Taiwan a rebellious province to be reunified with the mainland, by force if necessary, Taiwan insists on its rights as a self-governed entity.

What that self-governance looks like in practice and how far it should be pushed have been a source of dispute between Taiwan’s two parties, the Nationalist Party and the Democratic Progressive Party.

The rebellious youths in the movement say they are less concerned about what Taiwan calls itself — sovereign, independent or a self-governing area within China — than they are about the specific policies of the government.

As with the U.S. Occupy movement, there are no formal leaders or members among the white shirts. And similarly, there have been some signs that its decentralized approach could cause the movement to eventually peter out.

The wide-ranging causes pushed by various coalitions in the group have included opposition to a proposed nuclear power plant, current referendum laws and a service trade agreement with mainland China.

But the group’s biggest success to date has come on the original cause that brought it together — demanding military reform after a young Taiwanese soldier’s death while being punished by his superiors.

“None of us expected that protest would become what it did,” Liulin said in a recent interview, as he sat alongside other white shirts at the group’s makeshift headquarters — a small room borrowed from a friend’s medical association office.

A new kind of voice

Liulin, a doctor, had just finished his mandatory year of service in Taiwan’s military when he heard about the death of Hung Chung-chiu, 24. The soldier had died of a heatstroke while doing heavy exercise as punishment for carrying a camera phone on base.

To Liulin, the tragedy represented a larger pattern by Taiwan’s still relatively young democratic government of abusing its citizens and disregarding their civil rights. So under his online handle, “spicycop,” he posted a message on an online bulletin board asking whether others who were similarly outraged wanted to meet up.

Only 39 people responded to Liulin’s post, but they decided to send out a wider call for demonstrations on Facebook and other social media. The first protest attracted an estimated 30,000 people, according to media reports.

The second, held Aug. 3 in front of Taiwan’s presidential office, brought roughly 250,000 into the streets, according to several Taiwanese reports. Many in the crowd carried signs showing a giant eye shedding blood, an allusion to the Big Brother government in George Orwell’s novel “1984.”

They sang a song about revolution from the musical “Les Miserables,” substituting lyrics in the local Taiwanese dialect. They beamed the Chinese characters for “injustice” and “truth” onto the presidential office using LED lights. And at one point, organizers directed the crowd to hold aloft their smartphones to signal to the government that it was being watched by the people.

Within days, Taiwan’s leaders promised a special commission to investigate the past cases of military misconduct. Reforms were rushed through the legislature.

“In Taiwan, protests are always the work of a political party,” said Hou Han-jyun, a politics professor at National Taipei University. “It takes money, members and mobilization. These guys just posted something on Facebook. It required nothing.”

While some in the Taiwanese media have likened the protests to the Arab Spring uprisings, with their online origins and youth involvement, the white shirts say they aren’t drawing inspiration from any specific country.

Several coalitions are involved with the white shirt movement, but the core group behind the protests has adopted the name “Citizen 1985.”

In the interview, surrounded by stacks of fliers, banners and T-shirts emblazoned with a raised fist, Liulin and two others in the group described the movement as having a flat organizational structure. The other two men only identified themselves with their online handles: “Soul,” a 28-year-old construction worker, and “DKW,” a 29-year-old chemistry graduate student.

“The whole idea is that, just like online, it doesn’t matter who you are. Anyone can make their voice be heard,” DKW said.

The group often holds its meetings via Skype. When there are major issues to vote on, they type in “+1” or “-1.” Pamphlets are drafted online as Google documents so that everyone can chime in before a smaller group of volunteers edits them.

Several politicians have tried to reach out to the movement, according to the group and party insiders. But Liulin and others have not returned many of their calls, leery of being coopted.

“What we want is not complicated. We want the politicians to do what the people want,” Liulin said.

“Both parties are afraid of them,” said Hou, the professor.

An emerging identity

The group has emerged as the political conversation in Taiwan is shifting.

For years, debates about the nature of Taiwan’s independence have resulted in deadlock. Year after year, polls have shown a majority supporting Taiwan’s status quo as a self-governing entity and sidestepping the issue of independence.

But there is a growing sense of Taiwanese identity. The proportion of people identifying themselves as “Taiwanese” rather than “Chinese” has rocketed from 17 percent in 1992 to 54 percent last year, according to the Election Study Center at National Chengchi University.

In recent weeks, some political watchers have questioned whether the white shirt movement can sustain its momentum. Only about 60,000 people showed last month for the first protest since August’s demonstration at the presidential office. Some in the group attributed the lower turnout to the topic of the latest protest — a cross-straits service trade agreement — which is much harder to explain than a soldier’s tragic death.

“But honestly, the organization itself is not that important,” Liulin said. “If we can just spread this spirit and idea of getting involved and fighting for others’ rights, there’s no need for us to be here long-term.”

The group’s newest idea is to create a watchdog Web site on Taiwan’s legislature aimed at attracting young Taiwanese and explaining political issues. They compared it to Taiwanese coverage of baseball, a national obsession. There will be “pregame” analysis about upcoming policy battles, legislative “MVPs” and “worst players” from each party.

“People our age are too busy and too turned off by politics,” Liulin said. “But they do care. We just have to make it easier for them to be involved.”

Liu Liu contributed to this report.