After all the MS hoopla about trying to get the US to ban the use of GPL for publically funded software, here's a counter-argument:
http://opensource.mit.edu/papers/aigrain2.pdf
Abstract: This text provides a framework to discuss the consequences of licensing choices that are applied to publicly funded libre software. It discusses these choices from the angle of general public interest and policy. It concludes that one is led to prefer GPL copylefting licensing especially for any libre software component whose development is publicly funded, and when it is providing functionality that plays or may later play a critical role as part of the common infrastructure of the information society. At the same time, some interesting questions derive from a better understanding of the reasons that lead some to disagree with the choice of copylefting.
Regards,
-- Raju