Despite my own reflection that the Obama administration will likely move forward with whatever nanotech bill Congress puts before it, there may be some reasons for the administration to take a second look.
While the House overwhelmingly passed the bill last fall, it never made it through the Senate. And even if it had made it through the Senate, it was unclear whether Bush would have signed it into law as his administration was forcing a number of changes that are described here by Robert Service.
Among one of the more controversial Bush administration provisions was the removal of the requirement that a specific percentage of NNI funds be spent on Environmental, Health and Safety (EHS) research. And, frankly, that was the real change from all the other NNI bills.
It would seem that whatever form the bill finally takes will be satisfactory to certain factions within the nanotechnology community. But it seems the Obama administration is really taking science quite seriously, and may decide that they're not going to accept just any bill, but a good one.