Q+A: Japan PM-elect may ruffle U.S. on security issues

TOKYO (Reuters) - Japan's prime minister-elect, Yukio Hatoyama, has vowed to forge a more equal alliance with the United States while keeping ties with Washington at the center of diplomatic policy.

But a number of security issues could ruffle relations between the world's two largest economies, sparking concern among investors.

Following are questions and answers on some of the issues:

WHAT WILL HAPPEN TO U.S. FORCES IN JAPAN?

Japan hosts about 47,000 U.S. military personnel, a frequent source of irritation for communities near military bases, with many complaints of crime, noise and pollution.

Former Democratic Party leader Ichiro Ozawa drew criticism when he said earlier this year that most of the troops were not needed.

But the party's election manifesto makes no mention of a deep cut in troop levels, instead offering to propose amendments to the Status of Forces Agreement (SOFA) under which U.S. troops operate in Japan and to rethink a planned redeployment of U.S. troops.

Washington and Tokyo have agreed to ease what is seen as an unfair burden on the southern island of Okinawa by moving a 4,000-strong U.S. Marine Corps base from the heavily populated area of Futenma to the north of the island where fewer people live.

About 8,000 Marines will be redeployed from Okinawa, partly at Japan's expense, to the U.S. territory of Guam as part of the deal.

Washington is keen to press ahead with the project, which is supposed to be completed by 2014. Many residents of Okinawa, which suffered one of the bloodiest battles of World War Two, are dissatisfied with the plan for environmental and other reasons.

Democratic Party leader Hatoyama, who took over the party in May, has said the Marine base at Futenma should be moved away from Okinawa but he has not proposed an alternative location.

The party's proposed changes to the SOFA would include a requirement that U.S. forces make good any damage to the environment caused by their activities, a Japanese newspaper reported on Thursday.

Several cases of contamination have been discovered at sites returned to Japan after use by the U.S. military.

HOW FAR WILL JAPAN BACK U.S. MILITARY ACTIVITIES?

Hatoyama has said a Democratic government would not renew the mandate for Japanese ships on a refueling mission in the Indian Ocean in support of U.S.-led military activities in Afghanistan, although ships would not be brought home immediately.

The legal mandate for the mission, which the Democrats opposed in parliament, expires in January.

Hatoyama's predecessor, Ozawa, had mentioned an alternative option of sending troops to Afghanistan under a United Nations mandate, but the idea of putting soldiers' lives at risk is unlikely to gain popular support. No Japanese troops have been killed in action since World War Two.

WHAT LINE WILL THE DEMOCRATS TAKE ON NUCLEAR WEAPONS?

Japan has long been ambivalent about nuclear arms.

Many Japanese use the fact that Japan is the only country to have suffered nuclear attacks as a platform to campaign for the abolition of nuclear weapons.

Hatoyama backs President Barack Obama's calls for a world free of nuclear arms and has promised to uphold Japan's three "non-nuclear principles" banning the making, possession or introduction into the country of nuclear arms.

If he becomes prime minister, Hatoyama would likely call for a nuclear arms-free world in a speech at the U.N. General Assembly in September, Japanese media say. Hatoyama has also said he will seek a U.S. pledge not to bring nuclear-armed vessels into Japanese ports.

But Japan benefits from a nuclear "umbrella" provided by Washington, something many see as increasingly necessary given China's growing military might and North Korea's nuclear arms program.

(Reporting by Isabel Reynolds; Editing by Michael Watson)