At the Republican convention in New York City earlier this month, nearly three years after the 9/11 terrorist attacks, actor Ron Silver strode to the podium and delivered an emphatic statement of American resolve.

"We will never forgive. We will never forget. We will never excuse," he said to the cheering crowd at Madison Square Garden.

More than 600 miles to the south, an Episcopal priest was disturbed by the emphasis on vengeance he heard that night.

"Three years after the horrific events of Sept. 11, our nation is still breathing revenge and retribution," wrote the Rev. Brian Suntken in a Charlotte Observer editorial. "When will the true process of healing begin? When will our national leaders, many of whom assert religious affiliation,lead our nation into healing and renewal?"

Three years after 9/11, it is this divide--between forgiveness and retribution, healing and getting even--that shapes our country's foreign policy, our political discussions, and our country's spiritual framework.

Religious scriptures advocate for both forgiveness and retaliation. "An eye for an eye and a tooth for a tooth," say Exodus and Leviticus. "Turn the other cheek," says the Christian Gospel of Matthew. "You may kill those who wage war against you, and you may evict those who evict you," proclaims the Qur'an. But "I forgive those who do wrong to me," goes a hadith [saying of the Prophet].

Contemporary religious practice tends to emphasize forgiveness over retribution. "We should not seek revenge on those who have committed crimes against us, or reply to their crimes with other crimes," the Dalai Lama has said. Many other religious giants of the past century--Tolstoy, Gandhi, Martin Luther King Jr.--taught nonviolent resistance to evil.

Recent scientific research has demonstrated the healing effects of forgiveness. Everett Worthington, a professor at Virginia Commonwealth University, found that people who won't forgive wrongs committed against them tend to have more stress-related disorders, lower immune-system function, worse rates of cardiovascular disease, and higher rates of divorce. People who forgive, some studies claim, tend to live healthier and happier lives. Myriad self-help books have been written on the subject: "The Art of Forgiving" by Lewis B. Smedes, "Forgiveness Is a Choice" by Robert D. Enright, and "The Forgiving Self" by Robert Karen are just a few.

In this cultural and religious context, revenge was like a too-loud relative whose dinner-table rants made everyone uncomfortable. But after the 9/11 terrorist attacks, it became more acceptable to express a desire for revenge. "I want revenge," a woman told The Washington Post soon after 9/11. In The New York Times immediately after the event, columnist William Safire urged America's leaders to hit back hard: "We must pulverize them."

While the rawness of these feelings may have eased in the years since the attacks, the concept of revenge itself is coming under new scrutiny.

A Swiss report released the last week of August made headlines around the world for drawing a connection between revenge and pleasure. A University of Zurich team scanned the brains of male participants who passed money back and forth in a neutral setting. Those who made selfish choices instead of mutually beneficial ones could be punished by the other players. The researchers found that most players chose to exact some sort of revenge, even if it cost them some of their own money.

The desire for revenge was strongest in those players whose brains exhibited the most activity in their pleasure centers. Revenge, it seems, can be fun. And while that's hardly news, the study observed that the anticipation of this pleasure, and not necessarily justice, is in large part what drives us to seek revenge. In other words, we hit back hard because it feels good.

"The need to get even is universal," explained Washington Post reporter Laura Blumenfeld. Her 2002 book, "Revenge: A Story of Hope," tells the story of her confronting the Palestinian man who shot her Jewish father, a rabbi. While her father survived the attack, Blumenfeld was left scarred.

"Rather than trying to deny it, I wanted to try to figure out if there is a positive kind of revenge we can live with," she said. "We're all taught to forgive and turn the other cheek. But I was interested in revenge. How can something be completely bad if we all feel it?"

Blumenfeld's journey led her to Israel and then to the Palestinian territories, where she tracked down the man suspected of shooting her father. Instead of reconciliation and forgiveness, she wanted from him an acknowledgment that what he had done was wrong.

"What I found was that when he acknowledged that what he had done was wrong, there was a sense of peace and resolution," she said. "That's a very constructive kind of revenge. It's also a very American kind of revenge, a forward-looking kind of revenge that seeks to build up."