LEED refers to "Leadership in Environmental Efficiency in Design". It's a certification program run by the US Green Building Council, as a way to 'brand' sustainability, using a ratings system to establish how sustainable a building has been.
Various Federal agencies, State and local governments have supported sustainable building practices directly. Not just by endorsing LEED, but also by mandating that their own structures be LEED certified--a trend which appears to be spreading. Some places in California have also induced private developers to prefer LEED--in one case by having a separate queue for development review for LEED projects.
Developers are equivocal. While their is a growing recognition that LEED certified buildings do deliver in terms of lower construction costs and lower energy operating costs, LEED is regarded as complicated and time consuming. From developers, I hear: "It takes too long to certify a building--the approval process necessary to get a sticker is not worth the additional time it takes to do the development." In addition, receiving LEED certification required rigorous documentation of source materials and disposal options, resulting in additional cost an uncertainty.
LEED certification is controlled by the U.S. Green Building Council. While a non-profit, there are accusations that the cost of obtaining materials necessary to obtain and maintain certification are too high, and that the process of getting a building certified is tied up in development.
Perhaps city planners LEED certified, so they can check a building, rather than having a certified official at the LEED agency doing so. That would put the burden for development approval on local government. Planning and permitting would need to be able to evaluate LEED as well as compliance with building code, fire code, and zoning code, as well as assessing development impact fees. This seems possible-cities already use uniform national codes for evaluating traffic impacts, fire and structural safety. Most of planner labor (and stress) comes from local, highly specific issues regarding the zoning code. Applying an accepted national standard such as LEED seems plausible.