Some things we've come to count on. Old Faithful will erupt every 90 minutes or so. Halley's Comet will return every 75-76 years. The United States will always have the world's most powerful military.

That last item is especially important. We won the Cold War "without firing a shot," as Lady Thatcher put it, because the Soviet Union didn't want to risk a confrontation with our armed forces. Our military remains unparalleled. We have the only blue-water navy, the best-equipped, best-trained army and Marine Corps, and the world's most powerful air force. But unless we renew our financial support for the military, that supremacy in defense may soon be a thing of the past.

On Feb. 27, Director of National Intelligence Michael McConnell warned the Senate that China is building its military "to reach some state of parity with the United States" and "would become an increasing threat over time." That threat could develop quickly. The Chinese are pouring unprecedented amounts into their military. Last month, China's National People's Congress announced it would increase the country's military budget by 17.8 percent this year, to a total of $45 billion.

But even this sum grossly understates the true scope of China's buildup. The CIA estimates that Beijing shelled out $135 billion for its military last year, when you include foreign arms purchases, subsidies to military industries, China's space program and the 660,000 member "People's Armed Police."

John Tkacik, a retired diplomat who served with the foreign service in China, insists even that is low-balling it. He notes that the World Bank pegs China's total GDP in "purchasing power parity" terms at about $10 trillion in 2006 — meaning one gets about four times the "bang" for a "billion bucks" in China's arms industry than the Pentagon gets. Beijing's military spending, in purchasing power parity terms, would be around $450 billion — about what America spends.

China already boasts a fleet of 29 modern submarines, including 13 super-quiet Russian-made Kilo class subs and 14 Chinese-made diesel electric submarines. At least 10 more of these subs are in China's shipyards, together with five new nuclear ballistic missile and attack subs.

China's once-dilapidated air force already contains hundreds of Russian-made fighters, and reportedly plans to acquire at least 250 more. China adds more than 100 short-range ballistic missiles to its arsenal annually. Virtually all are aimed at America's ally, the democratic island of Taiwan, which China has long insisted it will annex someday.

The Chinese aren't coy about their long-term plans. Beijing last year announced its army will move "from regional defense to trans-regional mobility," including "long-distance maneuvers, rapid assaults and special operations." Its air force will expand "its capabilities in the areas of air strike, air and missile defense, early warning and reconnaissance, and strategic projection."

China now spends an estimated 4.5 percent of its $2.5 trillion GDP on defense (the United States spends 3.9 percent). To continue protecting our interests, we'll need to devote at least 4 percent of our GDP to defense. That's more than we've spent since 1995. But it's been a while since we faced a rising threat like the one China poses today. It's a serious military threat that demands serious military spending.