Q+A: How arms sales to Taiwan will impact Sino-U.S. ties

BEIJING (Reuters) - China warned the United States on Saturday that a new proposed sale of U.S. arms to Beijing's political rival Taiwan would seriously harm relations between the superpowers, another test of already strained ties.

China has claimed sovereignty over self-ruled Taiwan since 1949, when Mao Zedong's forces won the Chinese civil war and Chiang Kai-shek's Nationalists fled to the island. Beijing has vowed to bring Taiwan under its rule, by force if necessary.

Taiwan says it needs U.S. arms to update its military as China aims 1,000 to 1,500 short-range to mid-range missiles at the island just 160 km (100 miles) away at the closest point.

Here are questions and answers about the arm sales issue.

WHAT ARMS ARE IN THE PIPELINE?

An agency under the Pentagon proposed on Friday five separate sales, including 60 UH-60M Black Hawk helicopters, 114 Patriot "Advanced Capability-3" anti-missile missiles and a command-and-control enhancement for Taiwan.

Another round of Patriots, which are part of a larger $6.4 billion weapons package approved in 2008, was cleared on January 6.

Still pending is a study on whether Washington could upgrade Taiwan's aging submarine fleet.

Taiwan also has asked for dozens of F-16 jet fighters, a model the island's military already uses, but the United States has shown little sign of moving on this item.

HOW WILL CHINA REACT?

China loudly protests any U.S. arms sales to Taiwan and is likely to retaliate over the latest proposal, possibly by curtailing military-to-military relations with Washington.

China swiftly warned the United States on Saturday that the weapons packaged unveiled on Friday would seriously damage cooperation between the two global powers. [ID:nTOE60S0AG] After the separate Patriot missile deal was approved earlier this month, Beijing announced it had successfully tested emerging military technology aimed at destroying missiles in mid-air. [ID:nTOE60B00X]

The two sides are already at odds over currency, trade and Internet censorship issues.

China's "red line" would be the sale of F-16s, said Wendell Minnick, Asia bureau chief with Defense News, meaning it would take action against the United States.

China might, for example, decide to reduce cooperation with Washington on a number of important international issues such as Iran's nuclear program or cancel official visits.

This month, a Chinese Vice Admiral even suggested putting sanctions on U.S. firms that sell arms to Taiwan.

WHY DOES WASHINGTON KEEP SELLING ARMS TO TAIWAN?

Washington is home to a vibrant pro-Taiwan lobby, which wants the United States to beef up assistance for democratic Taiwan.

Accusations China intentionally keeps its currency undervalued and tramples on religious or other freedoms fuel pro-Taiwan sentiment among U.S. lawmakers, as well.

Washington, though it recognizes "one China" and backs Beijing over Taipei diplomatically, is also obligated under the 1979 Taiwan Relations Act to help defend the island. Taiwan has long seen the United States as its staunchest ally.

"There are legal issues and there are moral issues involved," said Bruce Jacobs, an Asian studies professor at Monash University in Australia.

HOW DO U.S. SALES CHANGE THE BALANCE OF POWER?

Analysts say the balance of military power between China and Taiwan is shifting decisively toward Beijing, leaving the island few options without U.S. aid in the event of attack.

Taiwan needs more advanced air and naval defenses to counter the modernizing Chinese armed forces.

Even with these new weapons, analysts say that without rapid, massive U.S. help, a concerted Chinese assault on Taiwan would eventually succeed.

(Editing by Jerry Norton)