Recent military news out of China includes double trouble. First, Beijing announced a jaw-dropping 18 percent jump in its defense budget - 5 percentage points more than last year's alarming rise -at the yearly meeting of the National People's Congress.

On top of that came news from an unidentified Chinese admiral via a Hong Kong newspaper that China is pretty far along in aircraft-carrier R&D - and could have one in the water by 2010.

This isn't good news.

The existence of a Chinese "flattop" program has long been rumored. Sure, some military experts scoff at the idea - often pointing out that carriers don't fit with China's military doctrine of "asymmetry."

That is, China's military buildup has focused on developing capabilities that are best suited to take advantage of an opponent's weaknesses - rather than one of trying to counter its obvious strengths.

Since the United States is one of the likely adversaries Chinese forces might confront (or at least deter), this means China hasn't been pursuing naval air power - an area where the U.S. Navy has nearly a worldwide monopoly (the United Kingdom, France, Spain, Italy, India and a few others have one or more carriers, mostly using Vertical/Short Take-off or Landing aircraft).

To counter America's overwhelming aircraft-carrier strength in a conflict over Taiwan, for instance, China has spent its defense dollars on possible carrier-killer weapons systems such as keel-cracking submarines and supersonic, sea-skimming anti-ship cruise missiles - not flattops.

(Critics will point out that carriers have significant vulnerabilities against a capable foe. Jaunty submariners brag those 100,000-ton "bird farms" are nuthin' but big, fat gray targets for their boats.)

So, if the experts are right, and China is pursuing a "David and Goliath" strategy against U.S. military might in the Pacific, why would Beijing build carriers?

First, it's always possible the recent news is wrong - just another badly sourced rumor coming out of Hong Kong regarding Chinese military developments.

Second, Beijing could be changing its strategy. It might be looking toward a more balanced naval force that includes aircraft carriers to project power deep into the Pacific. (With its broad expanses of open ocean, there aren't many other ways to operate in the Pacific theater.)

A third option: China may want to "show the flag."

China is, without question, a rising power - world's largest population, No. 2 energy consumer, No. 3 defense budget, No. 4 economy. And so on. It's an up-and-comer. Beijing may well think the time is ripe to unmistakably proclaim to the world: We're not just a regional power anymore.

That was the message of President Teddy Roosevelt's Great White Fleet 100 years ago. Flush with success in the Spanish-American War - defeating a major European power and adding possessions in the Atlantic and Pacific - TR sent a large naval task force on a global circumnavigation in 1907-09.

For years, Chinese ships rarely went overseas on military diplomacy missions known as "ship visits." This is changing as China develops its "blue water" (i.e., open-ocean) naval capabilities.

As opposed to provocative exercises of "hard power" (such as China's January test of a satellite-killer), a friendly ship visit, while still displaying strength, does so in a "soft power" way (think: velvet glove around the iron fist).

The U.S. Navy has successfully done this for years with ship visits to foreign ports of call. Locals visit the ships; sailors go on liberty. The people-to-people contacts help shape each side's views - hopefully in a positive way. (Sailors can be, er, rascals . . .)

So China might decide to build some carriers to symbolize its growing clout - with the intent of sending them around the region - or the world - just like the Old Rough Rider did.

But there's another possible purpose here, too.

With its limited navy, Beijing at present can't protect ships delivering overseas oil (and, soon, natural gas as well) from key Middle Eastern and African sources.

Those shipments are safe - because the U.S. Navy basically guarantees freedom of the seas free-of-charge.

That fact unsettles the Chinese - because it leaves their energy security at the mercy of America's good will. China can't continue to grow its white-hot economy, its influence - or fight a war - without access to foreign oil. Period.

So Beijing may see the need for a carrier task force, which it could to deploy to the South China Sea/Malacca Strait/Indian Ocean to protect its overseas oil supply. (Beijing is already financing a commercial port at Gwadar, Pakistan, near the Persian Gulf that could support those deployments.)

Of course, China could be looking at carriers for all the reasons above; the missions aren't mutually exclusive. A carrier can do ship visits, project power, protect sea lines of communication - and fight wars.

But carrier operations aren't easy - few others have mastered them like the U.S. Navy, with its near century of experience. The Soviets tried, but failed; others do it in a limited way. Beijing won't find it easy to truly join the club.

That said, the U.S. Navy should be well aware of Chinese President Hu Jintao's recent call for building a powerful navy, prepared "at any time" for conflict. Considering all this news, we'd be fools to take our current naval predominance for granted.

Peter Brookes, Senior Fellow in National Security Affairs, is a Navy vet and a former deputy assistant secretary of Defense for Asian and Pacific Affairs.