WITHOUT a doubt, the biggest event in philanthropy this year was the Giving Pledge*, a commitment by the wealthiest Americans to give away at least half of their fortunes.

The goals of the pledge, which was organized by Bill and Melinda Gates and Warren E. Buffett, were to stimulate discussion about philanthropy among the ultrawealthy and unleash a wave of me-tooism among others that would bring about “the Second Great Wave of Philanthropy,” in the words of Sean Stannard-Stockton, a blogger and philanthropic consultant. Indeed,the Giving Pledge and the attention it has attracted come at a time of economic weakness, high unemployment,raging political debates about whether to extend tax cuts or allow them to expire, the seemingly uncontrollable cost of health care — and the increasing income gap between the signatories and a vast majority of Americans. Pledge founders and signers and their supporters marvel that anyone would find fault with it. “I hardly know what to say,” Mr. Buffett said by telephone. “Philanthropy is a tradition in America.” Americans give away about $300 billion a year, he said, or the equivalent of 2 percent of gross domestic product. “It doesn’t seem to have done any harm in the country so far.”

Mr. Gates said the pledge and the discussions about it would improve the practice of philanthropy. “We will never be able to measure how much the group gets people to do more giving or do it in a better way,” he wrote via e-mail. “However, I think the impact is likely to be quite positive.”  In fact, Mr. Gates said, the pledge is a tool for addressing income disparity because it is a mechanism for the redistribution of wealth.

Mr. Stannard-Stockton said he was baffled by the criticism of the pledge. “Even if only one additional person took it up, at the levels of net worth we’re talking about, that could be $450 million more that would be out there doing something good,” he said.

“There’s something in the American DNA that is suspicious of enormous concentrations of wealth, even when directed toward the public good,” said William A. Schambra, director of the Bradley Center for Philanthropy and Civic Renewal at the Hudson Institute. “True, we are proud of our charitable impulse in the broadest sense, but we think of that in terms of writing a check to the local Red Cross or Boys and Girls Club, not billionaires doling out millions and perhaps influencing the political agenda.”

Bernard Marcus, the co-founder of Home Depot and a pledge signatory, said he saw no grounds for the current criticism. “All this money is going for charity to help people — what kind of numbskull would find something wrong with that?” he asked in a telephone interview. “Would they rather we bought yachts and built mansions?” Mr. Marcus and his wife, Billi, are making gifts to help Atlanta, their hometown, develop as a medical center that will rival Houston and New York. The Marcuses have donated heavily to bring biotechnology, particularly nanotechnology, to Atlanta, and their gifts have

helped generate jobs and innovative research.  “I’m very politically active,” he added, “but that has nothing to do with my charity.”

Alfred E. Mann, the founder of the MannKind Corporation and a pledge signer, said he thought concerns about philanthropists having undue influence on policy were overblown.  Mr. Mann said he had worried about whether the pledge would draw attention to income disparity, observing: “The differential between the wealthy and the poor is too great. I think the country has gotten too materialistic, and compensation in areas like entertainment and athletics and in corporations have

been outrageous.”

Marc Benioff, the billionaire founder of SalesForce.com, was not asked to sign the pledge. He has made a $100 million gift to the Children's Hospital at the University of California, San Francisco, the capstone of 20 years of gifts to support wide-ranging causes. The pledge, he said, was a good idea “very poorly executed.” He added, “Philanthropy should be about impact. I noticed a lot of the pledges were to multigenerational trusts and not to immediate philanthropic work. That’s not going to help anyone.”