guarantees a regression to centrist parties
The US's whole political system has been drifting rightward. Our center is more to the right than 20 years ago. So it does not matter if regression to center is happening as the center drifts into the fascist event horizon. Every possible "this is why it could never happen here" is possibly a single event away from being breached, then discarded. The US has had so many of our safety checks blown through, and the only people who can now prevent it have no desire to do so, because they're on the same team.
I'm sure you will be vigilant, but it takes the whole country. And a person may be smart, but people are dumb, panicky animals.
Cities are going to start looking like San Fransokyo (Big Hero 6) soon. Seems like an excellent idea though. If it really gets pursued, I wonder how it will interact with air travel, since I would imagine you would need no fly zones around these, at least at a certain height.