Mark Steyn, the Canadian columnist who lives in “blue” New Hampshire, is a true “red-stater” whose genius ranges somewhere between Mark Twain and Ambrose Bierce. He has got punch, wit, and smarts, and if he were teaching in a North American humanities department, they would send him off to “sensitivity training” for life, without parole.

In “America Alone” (Regnery, 224 pages, $27.95) Mr. Steyn aims his rhetorical sandblaster at three targets: Europe, Islam, and the welfare state. Why this trio? Europe is dying for lack of babies, Islam produces a surfeit thereof, and the fault lies, au fond, with the postmodern welfare state that relieves the individual of ever more responsibility while shouldering him with boundless guilt about past sins, such as racism and colonialism plus an equally boundless “respect” for “The Other.” Hence, he predicts: “Go to any children’s store in Amsterdam or Marseilles … Look at the women in headscarves or full abaya. That is the future.”

The facts are obvious. European women are having 1.4 children (1.1 in Spain) Muslim immigrants 3.5 — and six in places like Gaza. Play the compound interest game, and somewhere down the line, Europe will turn into “Eurabia.” Or as Mr. Steyn puts it in his inimitable prose: “By the next century, German will be spoken only at Hitler, Himmler, Goebbels and Goering’s Monday night poker game in Hell. And long before the Maldive Islands are submerged by ‘rising sea levels’ every Spaniard and Italian will be six feet under. But sure, go ahead and worry about ‘climate change.'”

Mr. Steyn has a point. In the West, only three nations are at or above the replenishment rate of 2.1: America, Israel, and Iceland. Skip that demographic speck in the Atlantic; it is too small and remote to make for generalizations. But why America and Israel? These two outriggers of the West have a “project” — an intact national identity, a warrior culture, and foes all around them. They simply cannot afford to die out, and they have a sense of themselves — call it a mission — that bellows: “We will never slink offstage!” Mind you, it was the Brits who invented “the white man’s burden,” and the French who proclaimed a “mission civilisatrice” for themselves. But that’s over and done with after two murderous world wars, innumerable defeats, and spirit-breaking upheavals. No wonder that they have chosen security über alles — a cradle-to-grave welfare state that stifles self-reliance and obligation to the future. Why should I have children? They deplete my time-budget as well as my wallet. Let the state take care of me tomorrow.

If the Europeans have thrown in the generative towel, Mr. Steyn plows ahead, the Muslims have not. They are lean, mean, and super-fertile, and they are thrust forward by a mighty sense of moral superiority as they look down on the decadent, libertine, and slothful West. Again, Mr. Steyn has a point. There is a lassitude about Europe that stands in stark, possibly tragic contrast to its glorious past — when its adventurers roamed the four corners of the globe as conquerors, when it produced everything, from the Renaissance to the fax machine, that makes up Western civilization.

This book is a relentlessly funny and felicitous polemic, but as in any polemic, its sparkling insights don’t quite add up to a watertight brief. Sentences are honed to the sharpest, wittiest point, but, in the end, they leave you breathless and with a sense of du trop. You begin to scratch your head once your look past the sheer delight of reading.

Eurabia? There are only 20 million self-righteous and embittered Muslims in Europe — and 430 million soi-disant Euro-weenies. It will take a while before the former overwhelm the latter — a couple of hundred years at least. Meanwhile, these secular and Christian folks are not amoebae or lemmings, driven to their demise by forces they neither understand nor control. If September 11, 2001, was no wake-up call, July 7, 2005, in Britain was, and so were the murder of Theo van Gogh in Amsterdam and a spate of foiled terror attacks since then.

Those Euros are beginning to see multiculturalism as an unforeseen passport to “parallel universes” in their inner and outer cities; they are taking a hard look at their mosques, and what is taught in them; and they are tightening up on immigration. The new buzzword is “integration,” which is a more correct moniker for “assimilation.”

Nor is America as exceptional as Mr. Steyn would have us believe. Berkeley is more like Berlin than Boise when it comes to the siren call of multiculturalism and “Otherism.” There is altogether too much guilt and too little pride in the West. But what a magnificent civilization it remains. It may run out of babies, but will it also run out of spunk?

Perhaps even Mr. Steyn doesn’t think so. His diatribe is a “device,” as the journalist’s lingo has it — a call to arms and to conviction. Eventually, appeasement must and will falter. Meanwhile, read this book and savor the fireworks. Grim as it is, it will make you laugh and then force you to think. Pedagogy could not be more pleasurable.

Mr. Joffe, publisher-editor of Die Zeit in Hamburg, taught American foreign policy at Stanford this fall, where he is also Abramowitz Fellow at the Hoover Institution. He just published “Überpower: America’s Imperial Temptation.”