TWO YEARS AGO, Taiwanese author Cheng Lang-ping predicted "China's Violent Invasion of Taiwan" just before the 1996 presidential election.

Now everyone is wondering if it is about to come true.The Chinese have massed 150,000 troops across the Taiwan Strait and test-fired unarmed missiles closer than ever before to the nationalist island.

President Clinton has responded by sending two American aircraft carriers, with supporting battle groups, "to be helpful if they need to be." And Secretary of State Warren Christopher, sounding uncharacteristically tough, promises "grave consequences" if the Chinese attack Taiwan.

But Beijing has not retracted its threat of invasion. Ominous editorials in both the Communist Party People's Daily and the military People's Liberation Army Daily warn that Taiwan's attempts to heighten its international profile "will bring grave disaster to 21 million Taiwanese compatriots."

The crisis is the worst since 1978 when Chinese shelling of Kinmen (formerly Quemoy) brought the Seventh Fleet into the Taiwan Strait. It is certainly more than the usual Chinese saber-rattling that precedes every Taiwanese election.

Yet most analysts remain convinced the Chinese are not ready to go to war. Even Taiwanese President Lee Teng-hui, favored to win the March 23 election, has advised his countrymen to "relax and go about their business."

Among the reasons for optimism:

MILITARY - China has the manpower but not the weapons for modern warfare. Chinese generals were reportedly appalled when they witnessed U.S. firepower in the Persian Gulf War, and they know some of it has been transferred to Taiwan.

Defense Secretary William Perry and London's International Institute of Strategic Studies agree that China lacks the air and amphibious capabilities for an invasion. "In the weeks it would take to suppress Taiwan's defenses," says the IISS, "China would face almost certain U.S. involvement."

Although no one in Washington has actually said American forces will help defend Taiwan, the deployment of two battle groups is a show of U.S. resolve.

ECONOMIC - China is Taiwan's second largest trading partner after the United States ($21 billion worth of Taiwanese exports make their to China through Hong Kong every year), and Taiwan accounts for 20 percent of all foreign investment on the mainland (estimated at $6 billion).

POLITICAL - An invasion of Taiwan would confirm Asian fears of the "China threat," something Beijing has tried to dispel. In the words of the IISS, "the political consequences would be momentous for a China seeking to modernize its economy through trade, commerce and international investment."

The only risk that cannot be discounted is that of an "accidental war."

Chinese missiles have been known to stray 200 miles off target. Last year they were tested 75 nautical miles from Taiwan. Last week they were being fired only 20 miles from Taiwan's northeastern port of Keelung and 30 nautical miles from the southwestern port of Kaoh-siung.

What happens if a stray missile hits a U.S. warship or a city in Taiwan? An American captain is allowed to retaliate if he feels his vessel is directly threatened, just as Taiwan's air force would go into action to protect a population center.

Then the war would be on.