US international aid programs are funded annually by Congress, which means they are by necessity subject to political unpredictability. US assistance for, say, immunications, student exchanges, or well-building programs routinely are ramped up, only to be quickly scaled back. Fortunately, many efforts are "sustained" even if funding is undercut: immunizations have long term benefits, exchange students have new skills, and new wells can last for years.

Providing antiretroviral therapy (ART) is different. A patient receiving ART needs medicine for the rest of their lives. If you stop the medicine, they die. There is no current prospect of a "cure" for AIDS, just long-term management.

Current US policy calls for providing millions of people with ART in coming years (two million through PEPFAR, plus additional numbers via the Global Fund and World Bank). This means that potentially millions of people in the relatively near future will have their lives directly dependent on the congressional appropriations process -- forever. I don't know of any other program in the history of US assistance where this degree of direct dependence has been true. It's quite easy to visualize troubling future scenarios.

Two ideas might help with funding unpredictability or burnout. First, a continued drop in drug prices will ease the dilemma. Perhaps some fraction of US funding could be steered immediately into research efforts targeted at "price bottlenecks". Second, US (and international) funders could take a multi-year view by establishing an endowed "AIDS Treatment Foundation". There are many examples of Congress endowing efforts in order to sidestep the short-horizon nature of US budgets. Such an initiative would assure at least some prospect of longer term commitment to patients throughout the world receiving ART.