Before we go nuts about an Arab company taking over some of our ports -- or for that matter a Chinese company taking over one of our oil companies or, say, a Russian company taking over an American nuclear power plant, or a Turkish company taking over an American chemical plant, or a Bulgarian company taking over a military supplier -- we've got to know what it means for them to “take over” something of ours.

In the global economy, who's them? Who's us? And what's a “takeover?” There's a world of difference between ownership, management, day-to-day operations, and control.

Ownership depends on who puts up the money. And these days money is coming from all over. The Emir of Dubai, who owns Dubai Ports World, has been investing worldwide in casinos, shipping lines, hotels, financial companies -- wherever he can get the best return. He's even bought the Essex House in New York.

Yes, there are some people in Dubai who hate America. A few of the terrorists who blew up the World Trade Center came from there. But face it: There are some people in lots countries who hate America, and a few of these people could become terrorists. Yet this frightening fact has almost nothing to do with the issue of ownership.

About 80 percent of American ports are already run by foreign companies. These companies usually hire Americans to do the day-to-day management. After all, global companies want the best talent they can get. Dubai Port World's chief operating officer is Edward Bilkey, who's an American. Its former American executive, David Sanborn, was just nominated to be U.S. Maritime Administrator.

And if this deal goes through, Dubai Ports World will probably keep most of the American executives who have been working for the British company that now runs the six ports in question because they've made the company lots of money, which is why Dubai Ports wants to buy it.

Whatever the arrangement, the day-to-day operations at the ports will still be done by American longshoremen, clerks, and technicians. And control over port security will remain with the U.S. government, the Coast Guard, Customs, harbor police, and port authorities, who make and enforce the rules.

I don't mean to minimize the real danger that a terrorist might sneak into an American port or plant a nuclear bomb in a container heading toward an American port, or a container mounted on a truck that crosses an American border headed for Kansas City.

But if that happens, it won't be because of the nationality of the company that has a contract to run a port, or of its managers, or even its workers on the ground.

It will be because this nation didn't want to pay for the gamma-ray monitors and radiation scanners and inspectors necessary to oversee more than a tiny percent of containers heading into America. Because we didn't want to bother with security checks and special ID cards with fingerprints and other biometrics for workers at all ports and border crossings. Because all of this would cost about $7 billion a year, out of a defense and homeland security budget of hundreds of billions, and might slow down commerce through our borders just a bit, and reduce some corporate profits.

You see, the real issue here isn't about nationality. It's about what we're prepared to pay for our security, and whether we pay mostly for a war in Iraq or we finally get serious about security here at home.