CAPE TOWN - Having met President Obama, I'm confident that he's a man of conscience who shares my commitment to bringing hope and care to the world's poor. But I am saddened by his decision to spend less than he promised to treat AIDS patients in Africa.

George W. Bush made an impressive commitment to the international fight against AIDS when he formed the President's Emergency Plan for AIDS Relief program. Since 2004, Pepfar has spent $19 billion to help distribute anti-viral treatments to about 2.5 million Africans infected with H.I.V.

Thanks to these efforts - and similar initiatives, like those spearheaded by the Global Fund to Fight AIDS, Tuberculosis and Malaria - the number of African patients with access to AIDS drugs jumped tenfold from 2003 to 2008. Since 2004, the AIDS-related mortality rate in sub-Saharan Africa has dropped 18 percent.

Yet President Obama added only $366 million to the program this year - well below the $1 billion per year he promised to add when he was on the campaign trail. (Pepfar's total budget now stands at $7 billion.) Most of the countries in Pepfar will see no increase in aid.

Under the Bush administration, about 400,000 more African patients received treatment every year. President Obama's Pepfar strategy would reduce the number of new patients receiving treatment to 320,000 - resulting in 1.2 million avoidable deaths over the next five years, according to calculations by two Harvard researchers, Rochelle Walensky and Daniel Kuritzkes. Doctors would have to decide which of the 22 million Africans afflicted with H.I.V. should receive treatment and which should not.

President Obama has also proposed to cut America's contributions to the Global Fund to Fight AIDS, Tuberculosis and Malaria (which had been increasing each year since 2006) to $1 billion in 2011, down from $1.05 billion this year. The fund, less than a decade old, has spent nearly $20 billion helping treat the worst diseases of the developing world. And it has become the premier model for results-driven aid; financing for projects is supplied incrementally, as programs show tangible progress - for example, in the number of AIDS-treating drugs dispensed. President Obama's plan to decrease support is deeply distressing; American financing for the fund should be increasing.

During my life, I've witnessed amazing advances in medical science. New treatments turn H.I.V. infection from a death sentence to a manageable illness. The cost of treating it is a small fraction of what it was 10 years ago. Meanwhile, more and more African nations have invested in the public health infrastructure needed to distribute AIDS drugs.

I appreciate that tough financial times require the United States government to cut spending. But scaling back America's financial commitments to AIDS programs could wipe away decades of progress in Africa.

As the 18th International AIDS Conference is held this week in Vienna, President Obama should reconsider his commitment to fighting the disease. Surely the richest country on the planet can find the means to fight this scourge.