Do not pick a fight with David Frum (former Bush speechwriter and stimulating author) or Richard Perle (former Assistant Secretary of Defense and eminence grise of foreign policy hard-liners) individually. And definitely do not pick a fight with them together. They are a formidable team. Their joint book, "An End to Evil: How to Win the War on Terror," provides a devastating reply to every single argument advanced by the left against this war, and provides an intellectual and moral boost to those who have supported it from the beginning.

They begin by reminding us that negativity and pessimism have greeted every stage of this conflict since 9/11. Remember the fears about the terrible Afghan winter and the predictions that our forces would face the same fate in those unforgiving mountains as had Britain’s in the 19th century and the Soviet Union’s in the 20th? And while the critics are now claiming that winning the war in Iraq was the "easy part," they said nothing of the kind before the war began.

Gen. Barry McCaffrey, for example, predicted that the United States might suffer as many as 3,000 casualties. The battle for Baghdad was supposed to drag on for weeks or months, and some commentators were dusting off their Stalingrad analogies. Others, like Sen. Edward M. Kennedy, suggested that Iraq had no connection to terrorists, but that if we attacked Iraq, we would "precipitate the very threat that we are intent on preventing — weapons of mass destruction in the hands of terrorists."

Frum and Perle analyze a number of weaknesses in our psychic and bureaucratic posture in this war. Their recommendations are both concrete and abstract.

Among the former, they recommend scrapping the regional bureaus at the Department of State. The "Near East" bureau, the "Western Hemisphere" bureau, and so forth lack clear missions and tend, in the authors’ words, to "stop representing America to the world and begin representing the world to America."

They further recommend radical reformation of the CIA, which may surprise those who think the CIA is peopled by hard-liners. In fact, the CIA was spooked (as it were) by the Church hearings in the 1970s and has been backpedaling ever since to the point where it is now dominated by liberals, which means, in too many cases, political correctness. "The CIA must re-emphasize linguistic competence — and must overcome its reluctance to check, double-check and triple-check the loyalties of native-born speakers of the languages in which we are most interested."

The book is nothing if not comprehensive in its recommendations. Here you will find the Frum/Perle and, more broadly, the conservative answer to questions like: how to deal with our "allies," like France and Saudi Arabia, who are really adversaries; how to manage the United Nations; undermining the Tehran mullahocracy; defusing the North Korean bomb; weaning Pakistan from Saudi-inspired (and underwritten) extremism; policing our borders (note to libertarians: it includes a national ID card); and leaning hard on nations like Egypt, Syria (and by extension Lebanon), Venezuela and others to cease all incitement of and support for terror.

But the greatest contribution of "An End to Evil" is its full-throated, passionate defense of the rightness of our cause. It is this more than anything else that will set liberals’ teeth on edge. In the Islamists, the authors argue, we are facing the moral equivalent of the Nazis and communists. Everywhere that the bacillus of Islamism has incubated it has wrought misery and destruction. Though the authors agree that we are not at war with Islam itself, they are not afraid to notice that within the Muslim world it is the Islamists, not the moderates, who have the wind at their backs.

Spreading democracy in that benighted part of the globe is not just benevolent, it is also the very best self-defense. "Our vocation," Frum and Perle write, "is not an imperial vocation. Our vocation is to support justice with power. It is a vocation that has earned us terrible enemies. It is a vocation that has made us, at our best moments, the hope of the world."

Mona Charen is a nationally syndicated columnist. Contact her by writing to mcharen@compuserve.com.