WASHINGTON - For years the Pentagon’s standing readiness plans required the country to be able to fight two major wars simultaneously. But no one anticipated what we face now: a war in Mesopotamia and another along the Mississippi.

We have journalist Malcolm Gladwell to thank for the idea that every social phenomenon has a dramatic “tipping point.” It doesn’t always work that way. And yet Hurricane Katrina is just such a moment. We are a big, strong country — and New Orleans will, somehow, survive — but you do get the sense, as President Bush finally arrived here after a month-long vacation, that a political hurricane is gathering force, and it’s going to hit the capital any day.

As we approach the fourth anniversary of 9/11, Americans are facing a different anguish from a different, but no less iconic city. New Yorkers, on behalf of the rest of us, absorbed Al Qaeda’s attack and came back stronger than ever. We begin the fifth year of a “war against terror” that has brought some gains, but has cost 2,000 lives and half a trillion dollars — and there is no end in sight.

And now: the Storm and the Flood, which have inundated the Gulf Coast in deadly water. This is, literally, an invasion of the homeland, and it will require a war-like response from a nation and a military already stretched thin. National Guard officials insist that they have enough men and women on hand to do the job, but common sense tells you that they could use the others stationed abroad. The U.S. Navy is dispatching supply ships to the region, but battling the waters that cover the region will require many more resources.