LHASA, Tibet Every bit on a par with questions about Iraq, terrorism and immigration, interrogators of 2008 presidential candidates ought to be asking: What are you going to do about the challenge of China?

That's because, I'm convinced after spending three weeks in China and Tibet, unless the United States gets its act together, our grandchildren will be living in a world dominated by the People's Republic.

China is simply inexorable in its pursuit of wealth, growth and power. It cares little about human rights, democracy, labor protections, fair trade rules or the environment. It is relentless in advancing its national interests.

Tibet is a microcosm of Chinese methods. What's going on here is pure colonialism. China invaded Tibet in 1950 ostensibly to free it from Buddhist "feudalism" and treated it brutally for a quarter-century.

Hundreds of thousands of Tibetans along with an estimated 30 million Chinese died in Mao Zedong's maniacal collectivization campaign, the "Great Leap Forward." In Tibet, the Chinese caused mass famine by trying to change the dominant crop from barley to rice, which does not grow in high altitudes.

Tens of thousands more Tibetans were killed when the Chinese put down a nationalistic revolt in the late 1950s, and almost all Buddhist temples were sacked and burned during the 1966-76 Cultural Revolution.

In the past 30 years, the level of violence is down, although last year Chinese border guards killed a young Buddhist nun trying to escape the country. Rather, China is simply dominating Tibet economically and politically and the presence of huge military bases emphasizes the futility of resistance.

As in the rest of China, much of what's happening here is impressive. The Chinese have built roads, schools, power lines, irrigation systems and communications in a country that still farms with plows pulled by yaks and whose rural people rarely bathe. Cell phones work better in Tibet even at the base camp of Mount Everest than in Washington, D.C.

China's crowning technological accomplishment here is construction of the world's highest-altitude railway line, connecting Lhasa and Beijing. The train furnishes oxygen to its passengers as it crosses a mountain pass at 16,000 feet.

The modernization, though, seems to be of, by and for the imported ethnic Han Chinese population, with the benefits merely trickling down to native Tibetans. The government claimed that in 2003 Tibet's 2.7 million people were 95 percent Tibetan and only 4 percent Chinese.

That's clearly ridiculous. Fully half of the capital, Lhasa, and smaller cities I visited seem to be populated by Chinese. Even most of the stalls at Lhasa's colorful Barkhor market are run by Chinese who often don't know what the Buddhist statues they sell represent.

The Chinese have rebuilt many of the Buddhist shrines they destroyed in the 1960s, both to promote tourism and pacify the deeply devout population. But they've limited the number of monks, and monasteries reportedly are heavily infiltrated by spies. Displaying pictures of the exiled Dalai Lama is illegal.

I think it's useful for celebrity-backed Western organizations such as the Free Tibet Campaign to alert the world to Chinese abuses, but there's no realistic chance the Chinese are ever going to release their hold on Tibet, which is the source of three of China's major rivers, supplies it with natural resources and serves as a missile testing base.

China's attitude toward the environment is epitomized here by the example of the magnificent Lake Yamdrok Tso, which will be drained to dust over the next 10 years to supply hydroelectric power.

China as a whole reminds me of the United States in the 19th century minus democracy, of course. Labor protections, environmental considerations, the popular will all are secondary to economic advancement. Much as the 20th century became the American Century, the 21st could well be the Chinese Century.

China's per capita gross domestic product still trails that of the United States by miles $7,600 versus $43,000 in 2006 but, with economic growth rates averaging 10 percent per year, China's GDP is now the fourth-largest in the world and could catch that of the United States by 2040.

In one dubious respect, the output of greenhouse gases, China is scheduled to catch up to the United States this year. The central government claims to be trying to improve the atmosphere, but in practice China is following the old U.S. dictum: "Pollution is the smell of people making money."

As the Bush administration has recently protested, China also has weak protections for intellectual property which means it steals Western technology and manipulates its currency to encourage exports and keep accumulating U.S. debt.

The Pentagon just reported that "China's ability to sustain military power at a distance, at present, remains limited," but it is developing systems and forces that could offset U.S. strength in the future, particularly in Asia.

What to do? Clearly, to me, the United States needs to vastly upgrade its education system and technology investment and resist China's unfair trade practices. China is not an enemy, but it's definitely a rival unless and until it becomes a democracy.

It's far from that now ruled by a communist hierarchy that adorns the country's currency with the image of a mass murderer, Mao. U.S. presidential candidates must say, in detail, what they'd do about the China challenge.

Morton Kondracke is executive editor of Roll Call, the newspaper of Capitol Hill.