Ed Feulner is president of The Heritage Foundation (heritage.org).

Think your life is a whirlwind? Try stepping onto the deck of an American aircraft carrier.

It's busier (and more efficient) than most major airports. As many as four jets can take off every minute.

The rest of the ship is a marvel, too. It's like a floating city, one able to generate a virtually unlimited amount of power from its nuclear engines. It creates enough electricity to light 100,000 homes. It can purify 400,000 gallons of water daily. It carries enough food to feed its crew for three months at sea.

In short, a carrier is a critical tool in our military arsenal, an irreplaceable asset that allows our military to project power anywhere, any time.

Of course, this much technology, know-how and military might doesn't come cheaply. Carriers are expensive to build, maintain and staff. And we no longer have as many as we need.

During the 1980s, the Navy estimated it would require 15 carriers to keep the high seas secure. Today, though, our carrier force is dwindling.

Last year Congress decided the U.S. could maintain only 11 carriers. Now, in another attempt to save money, the Navy says it can probably get by with just 10 carriers for awhile before it finally adds a new ship in 2015. Overall, today's Navy boasts only 280 deployable vessels.

That's a third less than experts projected we'd need in the ‘80s. Is the world really one-third safer than it was a generation ago? Let's hope so, because we have just half the number of ships we had at sea 15 years ago.

But simple numbers don't tell the whole story. In the years ahead, at least one carrier will be out of service at any given time for what's called a "Refueling and Complex Overhaul." That means our active fleet is already at 10 carriers, so decommissioning another one would actually leave us with only nine in service at any given time. That's simply not enough.

The Constitution gives lawmakers the power of the purse, so it's their responsibility to provide for the common defense. That means maintaining a powerful Navy. Lawmakers should insist the Navy keep 12 carriers in service.

One way to do that: Speed up the shipbuilding process. The next carrier is set to be finished in 2015. But it could be christened years sooner, if Congress would place the construction on a wartime footing (and we are, after all, at war). By hiring extra workers and running three shifts, the Navy could get the next carrier into service by 2012.

It's not as if other countries are standing still. China is building submarines at a frantic pace. By 2025, it could have five times as many subs in the Pacific as the U.S. There's no reason for China to become our enemy -- but there's also no excuse for Congress to allow our Navy to be so outgunned, just in case the Chinese become aggressive.

Building and repairing ships costs money. But it's more expensive in the long run to start from scratch. Once shipyards close, it's difficult to re-open them, since the skilled workers move on to other jobs.

As Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, put it during a recent speech at The Heritage Foundation, we need "a national debate about how much we want to spend on our security in these very dangerous times." Congress should start that discussion by insisting the Navy keep a dozen carriers in service -- and supplying the necessary funds. Our sprawling continental nation, bounded by two oceans, needs to be guarded by the world's most powerful Navy.

I was honored to be on hand when the newest carrier, the Ronald Reagan, was commissioned in 2003. I've also been on the main deck of the Nimitz to watch the amazing capabilities of the Navy first-hand. If we do the right thing, our country won't have to wait another seven years before the next great carrier comes into service.