Reactions as follows:
- I have to assume that Cameron was consulted and either acquiesced or actively encouraged Obama to give the speech, which inevitably was viewed as a crude attempt by a foreigner to interfere in British affairs in some circles. Since Obama is reasonably popular in the UK, it was probably a risk worth taking.
- The referendum has powerful international implications, so it was not inherently wrong for an American to talk about it in public.
- Putin and Marine Le Pen support Brexit, which pretty much tells you all you need to know about its merits.
- I have written about the impact of Brexit on the UK in the past, so I will not repeat myself. From the perspective of American foreign policy, any measure which leaves the EU weaker and more protectionist is a serious mistake.
- The euro has been a disaster for the EU. It was conceived less as an economic tool than as a symbol of increasing political unification, but saving it has become an end in itself and has thus (ironically) made nationalism the flavor of the month. That said, the EU remains, in the big picture, a success story, and the only beneficiaries of efforts to weaken it are noisome right-wing populists and the Russians.
Update: Trump says he supports Brexit. Need I say more?