Broadcaster, author, and biographer Michael Ignatieff dons yet another hat with his latest book: political theorist in the tradition of Isaiah Berlin, the Oxford professor whom Ignatieff profiled in a 1998 book. Ignatieff met with the late thinker many times over the course of a decade, and has now written an analysis of the current geopolitical crisis that owes much to Berlin’s influence. But Ignatieff’s concise, brave piece of critical thinking is not derivative; it brilliantly applies Berlin’s intuitions to the post-9/11 world.

Berlin believed that democracy’s core values can never be reconciled with each other, and that, at best, the system must opt for lesser evils. Ignatieff’s book attempts to articulate the least evil response to terrorism, always acknowledging, like Berlin, that no morally pristine options exist. When a democracy fails to respond to terrorist threats, it jeopardizes the security of its citizens; but when it wages war abroad and curtails liberties at home, it undermines the very principles on which it is based.

In concrete terms, Ignatieff views the war in, and forced imposition of a government on, Iraq as threats to the democratic beliefs in nonviolent conflict resolution and self-determination. He also presents the imprisonment of foreign nationals in Guantanamo with no access to the courts as an infringement of due process guarantees, and views the possible introduction of identity cards as an invasion of citizens’ cherished rights to privacy.

But such measures are not to be rejected out of hand, as they may be necessary, lesser evils. For Ignatieff, as for Berlin, tragic choices must be made to minimize evil. The core problem here is how a democracy can wage an effective war on terror, without selling its soul.

The book deftly argues for a measured response to terrorism on the basis of historic precedents. According to Ignatieff, unless a country is in a state of profound economic and political crisis, terrorists can seldom threaten its continued existence. Thus, the terrorist campaign of the Russian nihilists in the 19th century could not overthrow the tsarist state; only the chaos provoked by the First World War could allow the nihilists’ successors, the communists, to take over.

In the absence of a political and economic crisis, the most pressing threat to a democracy comes from within: an overzealous reaction to violence can start a state on the slippery slope to perdition. The risk, Ignatieff argues, is that measures taken to confront an extraordinary threat will deform a democracy. He attributes democratic Germany’s gradual transformation into a dictatorship in the 1930s to its willingness to prioritize order over civil rights.

When Lincoln summarily imprisoned opponents of the draft during the Civil War, the president argued that he was administering medicines to a sick body politic and that when the patient recovered, he would naturally cease prescribing the medicine. Ignatieff doesn’t buy this argument, believing that powers, once taken, are seldom voluntarily relinquished.

He is also brave enough to argue that overreaction to terrorism is natural. When faced with a possible threat to their lives, the majority in a democracy will often accept discriminatory treatment of a minority, such as the internment of Japanese Candians in the Second World War. A country’s leader gains more political capital by pandering to this majority than protecting an often loathed and mistrusted minority. Thus, Ignatieff opposes the common knee-jerk emergency reaction of allowing a nation’s leader to be the sole arbiter of its response to the crisis. Faced with an intractable, long-term struggle against global terrorism, Ignatieff proposes that U.S. courts, media, and legislature not take a back seat to the president in dictating how America wages this campaign.

While many have compared the attack on the World Trade Center to Pearl Harbor, Ignatieff compares the hijackings to the wave of communist bombings that swept America shortly after the Russian revolution. After a suicide bomb damaged the attorney general’s house, he ordered the detention of 5,000 “enemy aliens” without warrants with no possibility of judicial review.

His chief deputy in conducting the raids was the young J. Edgar Hoover. As it turned out, the perpetrators of the bombings were isolated extremists, their views and methods rejected by the vast majority of the citizenry. The state’s usual investigative and punitive powers, even limited by the cumbersome due process guarantees, would have sufficed to neutralize the threat. Through this example, Ignatieff demonstrates precisely how overreaction can infect a democracy: Hoover learned disrespect for civil liberties here and applied these lessons throughout his long, influential career.

Like his mentor before him, Ignatieff proposes that skeptical, careful thinking during times of crisis can protect what is essential, what is special, about the Western way of life.