Members of the Japanese Ground Self-Defense Force prepare for the arrival of new troops at the compound of the U.N. peacekeeping mission in Juba, South Sudan. (Albert González Farran/AFP/Getty Images)

Last year, in the middle of the night, tens of thousands of Japanese protesters gathered outside their country's parliament. Inside, legislators were engaged in a melee, as members of Japan's biggest opposition party tried to grab a microphone from the chairman of a special parliamentary committee. The dissenters had the support of the protesters outside. With control of the microphone, the chairman could initiate a vote on a question that has divided Japan since its defeat in World War II: Should Japan reinstate its army's ability to use force in conflicts abroad?

Eventually, lawmakers from the governing party formed a protective cordon around the chairman, and the ensuing vote at least nominally brought Japan's decades of pacifism to an end. Prime Minister Shinzo Abe successfully argued that Japan needed to flex its muscles, given North Korea's persistent belligerence and unpredictability, as well as neighboring China's intimidatingly large army.

On Monday, however, Japanese forces were actually deployed — but not to any hot spots in East Asia. Instead, dozens of Japanese soldiers landed in Juba, the capital of South Sudan. By mid-December, 350 of them will be stationed there as part of a peacekeeping unit that will be authorized to use guns if needed to protect civilians, U.N. staff or themselves.

The Japanese contingent is made up of trained engineers whose main mission is to engage in construction projects, but there are also plans for them to take a more active role in peacekeeping under an expanded mandate stemming from the security measures approved last year.

Japanese troops have been deployed as part of U.N. peacekeeping missions before — starting in 1992 in Cambodia and including to South Sudan in 2012. Last year's legislation means that the Japanese troops can now use weapons, notably in rescuing U.N. staffers who come under attack and defending U.N. peacekeeping facilities.

U.N. compounds and peacekeepers have increasingly come under attack in Juba and elsewhere in South Sudan, so it is not unlikely that the new Japanese arrivals may have to use their guns.

In February, fighting broke out between youths from rival ethnic groups within a U.N. compound housing thousands of displaced people. The violence escalated after government forces entered the camp. Peacekeepers fled the scene, and dozens of displaced civilians were killed. An inquiry by the United Nations said the organization and its peacekeepers failed through a “combination of inaction, abandonment of post and refusal to engage.”

In July, when fighting broke out between troops loyal to the South Sudanese president and his rival — the former vice president — two Chinese peacekeepers were killed and U.N.-marked vehicles came under fire, including a convoy carrying senior officials from the U.S. Embassy. During the spasm of violence, soldiers ostensibly under the control of President Salva Kiir terrorized a compound where foreign aid workers lived, killing a South Sudanese journalist and raping several of the women trapped inside. U.N. peacekeepers, stationed less than a mile away, did not respond to repeated requests for help.

Peacekeepers, especially in South Sudan, have a limited mandate. They can use force in defense of civilians or U.N. personnel, but they can't use force against an opposing army — in this case, the Sudan People's Liberation Army, which is loyal to Kiir. Yet that army has perpetrated much of the recent violence against civilians, foreigners and even U.N. peacekeepers. It is the only armed force in Juba, after soldiers loyal to former vice president Riek Machar retreated in the wake of July's bloodshed.

About 12,000 peacekeepers from across the world are deployed in South Sudan.

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