Taiwan is far more vulnerable to attack from China than is generally recognized because its isolated military has fallen behind technologically, according to a new and highly classified Pentagon report.

The 40-page report points out "a host of problems" with the Taiwanese military's ability to defend against airplanes, ballistic missiles and cruise missiles, said a Clinton administration official familiar with it. It concludes that Taiwan's military capability has been weakened by the island's diplomatic isolation, and faults the military for allowing poor security at its bases, for tolerating bitter interservice rivalries, and for failing to develop a professional corps of senior enlisted troops to operate its weapons systems.

"There is no other military in the world that experiences the kind of isolation Taiwan's does," the administration official said in summarizing the report. "They don't train or have contacts with anyone. And as warfare has become more complex, it has become more difficult for them to handle all these new technologies."

The Pentagon report comes after a spell of unusually bellicose Chinese rhetoric over the presidential election in Taiwan, which concluded with the victory earlier this month of a pro-independence candidate opposed by Beijing. By validating reports of Taiwan's military inadequacy, the Pentagon view could sway a decision by the Clinton administration, which is wrestling with the nettlesome question of whether to sell four sophisticated Aegis destroyers and other advanced military gear to Taiwan, including long-range radar that could look thousands of miles into the Chinese mainland.

The administration is expected to make a decision on the sale by the end of April, when a Taiwanese delegation is scheduled to arrive here to discuss the requested arms. A senior Chinese official warned earlier this month that a U.S. transfer of high-tech military equipment to Taiwan would be considered a hostile act and would be "the last straw" in U.S.-China relations.

"I can't begin to tell you how tense and sensitive this is," the administration official said in requesting anonymity.

"The drafting of this was an extraordinarily difficult process, because it is such an extremely sensitive issue," echoed a Pentagon official involved in producing the study.

The report was produced by officers on the staff of the Joint Chiefs of Staff and by officials in the policy formulation office of the Office of the Secretary of Defense. Overall, it outlines "not a very pleasant picture" of Taiwan's defenses, the Clinton administration official said. He added: "These guys don't know how to do a lot of this stuff."
 Taiwan's armed forces essentially have sat out the information revolution, the report argues, and so have failed to assimilate several generations of advances in information processing. While such advances have attracted public notice in the military arena for leading to precision-guided munitions, they also have led to less flashy but equally significant increases in the ability of modern militaries to first detect fast-moving and hidden targets, then transfer that information to weapons systems and finally guide the fired weapon to its target.

A defense official at the Taiwan government office here declined to comment on the report. The Taiwan government is believed to be aware of the report's existence but is not thought to have seen it yet. Senior Taiwanese officers have said in recent interviews that they understand they have severe weaknesses, and say that is why they want Aegis ships, which feature a high-powered phased-array radar able to simultaneously track and target hundreds of incoming missiles and aircraft. "Antimissile defense and air defense is our highest priority," Adm. Lee Jye said last month.

But some U.S. defense experts argue that the Aegis ships would be too sophisticated for the Taiwanese military to use properly and also would, at about $1 billion apiece, soak up funds better spent on other gear. "The Aegis could help with sea-based defense, but it doesn't speak to their core military problem of island-wide air defense," said Michael Swaine, a specialist in the Chinese military at Rand Corp. "What their situation demands is a lot of software integration, especially linkages between their army, navy and air force."

The report is the first in a series of studies of the military balance between Taiwan and China ordered by the Pentagon's policy office. Generally, that office, which is dominated by civilians, is seen as taking a harder line in favor of Taiwan than does the uniformed U.S. military. The policy officials argue that for the Clinton administration's policy of engagement with China to succeed, it is necessary to maintain the cross-strait military balance, ensuring that neither is able to impose its will on the other. The new report implicitly argues that that balance now may be tilting too much in favor of Beijing.

Richard Fisher and William Triplett, two China specialists associated with conservative congressional Republicans, said they believe the Pentagon is deliberately suppressing the report. "This report is extremely significant," said Fisher.

The Pentagon report was completed in January, but since then has been labeled a "draft." Some congressional aides suspect it has been kept in that form because it makes it easier for the Pentagon to refuse to show it to them. The report has been widely discussed in foreign policy circles, but very few people actually have been permitted to read it.

Pentagon spokesman Kenneth Bacon responded that the report isn't being suppressed. In addition, he said, a planned briefing to Taiwanese officials was postponed simply for logistical reasons. "We always planned to brief the Taiwanese on the contents of the assessment before releasing it to the appropriate people in Congress," he said. He declined to discuss the contents of the report, citing its classified nature.