CHICAGO - If the Bush administration gets its way, defense spending next year will be $394 billion, or about $100 billion higher than in Bill Clinton's final year. The United States has the most powerful military on Earth. We now spend six times more on defense than the next 15 countries combined. And you know what? It's not enough.

Despite the swelling budget, there is still a big gap between our resources and the administration's ambitions. The president's new strategy proclaims that we're not only going to meet any military challenge that may arise, but we may attack any country we see as a developing threat. If we're serious about that, even an unlimited budget won't suffice.

The administration gives us a glimpse of what to expect. The president's budget calls for piling spending increases upon spending increases, boosting national defense outlays to $442 billion by 2007 - up by nearly 50 percent from 2000.

But among conservatives, this financial commitment is seen as pitifully inadequate. "A year into this activist foreign policy, the defense agencies that will prosecute the war on terrorism remain starved of resources," declared military historian Frederick Kagan in an article in the hawkish Weekly Standard. "Increases of some $100 billion annually or more - over and above the increases already called for - will be necessary to provide for a defense establishment able to fulfill the president's national security strategy."

That strategy is an extravagantly ambitious one. Making it our job to prevent the proliferation of weapons of mass destruction is like trying to drink the oceans dry. The Pentagon says at least 25 countries have or are trying to get "nuclear, chemical or biological weapons or the means to deliver them." Every action we take to forcibly disarm a potential threat gives other nations additional incentive to acquire such armaments so they can avoid that fate.

Iraq is first on Mr. Bush's list, and the administration admits that the war and its aftermath could cost up to $200 billion. Unlike in the 1991 Persian Gulf war, we may not find many other countries willing to share the sacrifice in either blood or treasure. Estimates of the force required to occupy the country and maintain basic order start at 100,000 troops - a number that could go higher if Iraq's many factions want to fight one another, or us.

Even though that war hasn't yet been fought, the administration's allies are urging strong action against North Korea, which recently acknowledged pursuing nuclear weapons - and, in fact, probably already has them.

An editorial in The Wall Street Journal, which often echoes hard-liners inside the administration, called for firm measures to get rid of the North Korean government, arguing that "a new government in Pyongyang is probably the only sure nonproliferation policy."

The same logic may hold for Iran. Going to war with either regime would make the pending hostilities with Iraq look like a day at Disney World.

But stopping proliferation is not a one-time fix. University of Chicago political scientist John Mearsheimer, author of The Tragedy of Great Power Politics, says, "It's not viable just to conquer and occupy a country to get those weapons." That's because the next government may also want to acquire nuclear weapons, even if it's a democracy - as democracies such as India and Israel already have. "You have to stay forever," he warns.

Are we prepared for the sacrifices of this grand mission? Not likely, given that we lack even the will to bring basic order to Afghanistan - which not long ago was perceived, accurately, as an urgent problem demanding long-term attention. If the American people weren't willing to accept a major commitment in Afghanistan, despite its role in the Sept. 11 attacks, why would we be willing to do it for Iraq or some other country that hasn't attacked us?

Even a superpower will find out sooner or later that there are limits to what it can control in the world. At the rate we're going, it will probably be sooner.

Steve Chapman is a columnist for the Chicago Tribune, a Tribune Publishing newspaper. His column appears Tuesdays in The Sun.