Q+A: Why do U.S.-China military ties matter?

BEIJING (Reuters) - The United States and China said on Monday they needed to strengthen military ties in order to avoid missteps that could spiral into dangerous confrontation.

Here is an explanation of the problems in China-U.S. military ties, and why they matter:

WHY ARE THE COUNTRIES TRYING TO DEEPEN MILITARY TIES NOW?

U.S. Defense Secretary Robert Gates is visiting Beijing to bolster military ties a week before Chinese President Hu Jintao visits the United States, and a year after Chinese anger over U.S. arms sales to Taiwan curtailed Sino-U.S. military contacts.

After that row, Beijing and Washington also argued over how to handle rival Asian territorial claims in the South China Sea and over U.S.-South Korea joint exercises in the Yellow Sea near China.

Those disputes did not lead to military confrontations, but they were a reminder that China's growing military strength is increasingly pressing up against the big U.S. military footprint across Asia and the Pacific.

The Obama administration has said it is committed to maintaining that presence, but it says it wants dialogue with China's People's Liberation Army (PLA) so the two forces avoid mistakes, such as collisions, that could blow up into bigger conflicts.

Hu's visit offers Obama an opportunity to make his case for closer military ties, and Gates's visit will pave the way for that summit.

WHAT HAS GONE WRONG WITH MILITARY TIES IN THE PAST?

Military relations have gone through several rounds of modest warming and abrupt cooling since China and the United States established diplomatic relations in 1979.

China has often curtailed military ties to show its anger over issues like Taiwan.

The two countries have repeatedly quarrelled over Taiwan, the self-ruled and democratic island China claims as its own and whose defenses the United States is bound by law to aid.

After the PLA used gunfire and tanks to quell pro-democracy protests in China in June 1989, Washington suspended military contacts and arms sales. Since then, some Americans have argued there is little value in courting the PLA.

"Over the past three decades, security cooperation between the defense-military establishments of the United States and the PRC (People's Republic of China) has been the exception rather than the rule," David Finkelstein, an expert on the Chinese military with CNA, a group in Virginia that advises on security issues, wrote in a recent survey of U.S.-China defense ties.

"Both sides have perceived the costs of suspending military contacts as near-negligible," he wrote.

WHY DO THESE PROBLEMS MATTER?

They matter because China's military is growing stronger, while the United States keeps a big presence in countries and seas near China, and that could be a recipe for dangerous miscalculations.

China and the United States are not thought remotely likely to go to war against each other. Still, Taiwan remains a potentially volatile dispute, and analysts say missteps and accidents at sea or in the air could spiral into destabilizing confrontations.

Such clashes have happened in the past, and China's growing military reach heightens the risk of more.

In 2001, a Chinese fighter plane collided with a U.S. surveillance aircraft in the skies near China, killing the Chinese pilot and forcing the U.S. plane to land on a Chinese island. The resulting diplomatic standoff took over a week to defuse and bruised relations.

There have also been jostling incidents between U.S. naval and surveillance ships and Chinese ships in the South China Sea.

WILL GATES'S VISIT OVERCOME THESE PROBLEMS?

Gates's visit may help draw the two militaries closer together, restoring some of the exchanges that were curtailed in 2010. But nobody expects major breakthroughs.

This is a gradual process that could easily again go into reverse.

"In the ups and downs in Chinese-U.S. relations, military ties are always the first to suffer casualties," said Jingdong Yuan, a professor at the University of Sydney in Australia who specializes in Chinese security policy.

"Unlike other aspects of bilateral relations where there are mutual interests, especially in economic ties, in military ties really neither side seems to think they're gaining anything so it's easy, especially from the Chinese side, to use them to make a political statement whenever the U.S. side does something that the Chinese considers detrimental to its interests," said Yuan.

(Reporting by Chris Buckley; Editing by Daniel Magnowski)