Probably nothing that political... There was a redefinition that had the 7 base units be derived from the 7 fundamental constants. So, fixing the constants at a particular value instead of the other way around.

Possibly might have something to do with being able to accurately and precisely measure certain things before it can be definitely accepted... Plus, slow moving wheels off organisation... Especially if you are proposing to change fundamental measurement ideas... No big deal for every day life, but pretty important for experimental physicists (and other fields).,