Board up the windows in D.C.

SOME NATURAL disasters -- especially earthquakes -- strike without warning. As we have seen in Kashmir, they are the ones that do the worst damage. Other disasters, however, can be foreseen, such as the hurricanes that have pummeled the United States in recent months.

The disaster about to engulf Washington, D.C., is more like a hurricane than an earthquake. That is to say, you can see it coming.

The first intimations of its approach are small squalls. A succession of these struck lately. The one to watch is currently raining on Karl Rove, President Bush’s most trusted advisor, and I. Lewis “Scooter” Libby, chief of staff to Vice President Dick Cheney.

Like the financial squalls that have simultaneously struck the top Republicans in both Houses of Congress, these may conceivably turn out to be mere storms in teacups. But there are three reasons to think otherwise.

Let’s just assume for a second that Messrs. Rove and Libby did knowingly tell journalists that Valerie Plame was a CIA “covert operative” in order to discredit her husband, former Ambassador Joseph C. Wilson IV. Exposing a secret agent is a crime. Now the chances that it was authorized by the president himself are relatively small; and the chances that his authorization was recorded on tape a la President Nixon are even smaller.

So this is unlikely to be the next Watergate. Still, if his most trusted advisor goes down, the president will not merely be a lame duck. He will be a Peking duck. His enemies will be able to flake him off the bone and wrap him in Oriental pancakes.

The second reason why this is likely to be a hurricane is that so many people have an incentive to make it one. Watergate not only destroyed Richard Nixon, it also made the reputations of prosecutors such as Archibald Cox and reporters such as Bob Woodward. So you can always assume heroic levels of professional commitment when a quality scandal such as this one comes along.

At the same time, aggrieved sources within an administration have a powerful incentive to leak. We finally learned who “Deep Throat” was this year -- and only because W. Mark Felt decided to ‘fess up after 30-plus years. If that doesn’t prove that American journalists know how to protect their sources, I don’t know what more you want.

So let’s just ask ourselves how many people -- particularly those associated with intelligence gathering -- might have a grudge against Bush. I should think there are enough potential Deep Throats in Washington today to form a baritone male-voice choir.

The third reason to expect a hurricane is simply poetic justice. The ancient Greeks had a term for those who are intoxicated by their own power into thinking themselves equal to the gods. That word was “hubris.” Those who succumb to it are doomed to be brought low by the implacable goddess Nemesis.

Nemesis is no slouch when it comes to devising appropriate forms of divine retribution. This time she has really excelled. The way things are going, the trials of Saddam Hussein and Karl Rove could happen more or less simultaneously.

Imagine this as a kind of legal stereo. In Baghdad (following Slobodan Milosevic’s example at The Hague), Hussein will use his trial as an opportunity to excoriate the conduct of the invasion of Iraq. Meanwhile in Washington, special prosecutor Patrick Fitzgerald will expose the cynicism with which it was planned and sold to the public.

Bush’s approval ratings are down to 39% -- the lowest of his presidency. They have further to fall as he continues his bizarre reenactment of the 1970s, complete with military quagmire, oil-price shock and now hurricane-force scandal.

Still, don’t get too excited. After all, he is only the president. By definition he is replaceable, in 2008 if not before. Spectacular though the collapse of his reputation may prove to be, the net effect on the United States -- perhaps even on the Republican Party -- may be much less than his and the party’s detractors assume.

Having recently written a book with the subtitle “The Rise and Fall of the American Empire,” I am regularly asked when exactly I expect that fall to happen. The answer is not this year, next year or the year after that. Not this decade. And quite probably not this century either.

For the American Empire is young by historical standards. The United States was founded 229 years ago; its era of overseas expansion has been going on for just over a century.

Compare that to Rome, which was founded in 509 BC. If you date the Roman Empire from the elevation of Augustus to the death of Theodosius, it lasted 422 years. If you date it from the foundation of the Republic to the sacking of Constantinople by the Turks in 1453, it lasted 1,962 years.

If I had to push the analogy all the way, I would say we are currently somewhere around the reign of Trajan, who overextended the empire by invading Armenia, Mesopotamia and Syria but kept the Roman plebs happy with plenty of “bread and circuses.”

Yet Trajan’s excesses were easily rectified by his successor, Hadrian, who withdrew west of the Euphrates and carefully consolidated the large European and North African empire that remained.

So who will the American Hadrian be? I have no idea -- but I hope it will be John McCain. Once the impending political hurricane has passed, the United States will need someone of his caliber to consolidate its empire -- and clean up the mess left by the circuses at home.