There's a massively underused middle ground -- instead of 1 or 50 different systems we could have a small N. One example would be emissions standards, where N is basically 2 -- the federal standard and the California standard, with some states choosing to use the California standard instead of the federal standard. This happens because that's their only 2 choices because of weird historical events, but imagine it happening by deliberate choice where the other states co-operate more with California in setting the more restrictive standard. States should be co-operating more often.