An American military intelligence officer, asked some years ago how far the Chinese could project their military power, answered only half-jokingly: "About as far as their army can walk."

That is changing rapidly today as China's leaders fuel the budgets of the People's Liberation Army, which comprises all of their armed forces. Says a new report from the Council on Foreign Relations, the think-tank in New York, China is driven both by "a clear operational objective," which is to take Taiwan, the island Beijing claims, and "a clear strategic objective," which is to be a modern power.

China's military priorities are four: the navy, in which submarines take first place; the air force of jet fighters and long range bombers; space, not only threatening U.S. and other satellites but putting up their own; and what the Chinese call the Second Artillery, their land-based nuclear weapons including 1,000 missiles aimed at Taiwan.

"Submarines currently dominate China's naval development," say analysts Andrew Erickson and Andrew Wilson, writing in a recent U.S. Naval War College Review. China has long been rumored to be eager to build aircraft carriers but for now, these analysts say, discussion of submarines "is much more advanced and grounded in reality than that of carriers."

At first, the Chinese got submarines and submarine technology from the Soviet Union and, to a lesser extent, from France and Israel. Now they are building their own. Moreover, they are retiring older boats and replacing them with fewer but more advanced boats, both diesel-electric and nuclear powered.

Over the next eight years, the Chinese plan to have in operation five Han- and six Shang-class nuclear-powered submarines whose mission will be to attack aircraft carriers and other surface warships. In addition they will have 15 Song and 17 Ming diesel-electric boats with the same task but closer to home, according to Global Security, a private research organization.

China also plans to put to sea a nuclear-powered submarine, Jin, armed with ballistic missiles tipped with nuclear warheads and to retire an older boat, Xia, with the same arms. An analyst in Taiwan, Cheng Dai-ch'eng, wrote: "The communists are probably not going to use their submarine-launched missiles against us, but against the United States who may come to our aid in future conflicts."

The Chinese have vigorously denied that their navy is a threat to other countries. An article in Huangiu Shibao, a government newspaper, asserted last month that Americans were "talking nonsense about details of China having expanded its submarine fleet." Some Americans agree, at least in part, saying it will be many years before Chinese submarines will be able to challenge the U.S. Navy.

Even so, Chinese military planners have revised their operational thinking on attack submarines. Before, they patrolled close to China's coast to repel an invasion. Now, says a fresh study from the U.S. Office of Naval Intelligence, they are deployed farther out to resist invasion, protect territorial sovereignty and safeguard the nation's maritime rights.

Chinese submarines have been detected well past what the Chinese call the first island chain that runs from Japan through Taiwan and the Philippines to Indonesia. "Offshore defense" evidently calls for Chinese submarines to venture "as far as the PLA Navy's capabilities will allow it to operate," the Office Naval Intelligence says. Some Chinese officers suggest that a future objective will be patrols as far east as Hawai'i.

A critical question is Chinese seamanship. An American naval officer has 500 years of seagoing experience behind him, 250 years of the British navy and 250 years since the sailing ships of Salem plied the seven seas and John Paul Jones founded the U.S. Navy. American submariners have 100 years of experience, since the early 20th century, to draw on.

In contrast, China in 5,000 years of history has produced only one great sailor, Adm. Zheng He or Cheng Ho, who sailed the Pacific and Indian oceans in the 15th century. Chinese submariners, hampered by the Sino-Soviet split and the chaos of the Cultural Revolution in the 1960s and 1970s, are just beginning to learn their craft in highly complicated vessels.

U.S. military leaders, including Secretary of Defense Robert Gates, have for many months contended that the Chinese should be more open about their military intentions, including why they are expanding their submarine fleet. Pointing to China's surging economy that pays for the boats, an American submariner, wondered out loud: "I suppose they do it because they can."

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.