No spike in South Dakota. No shutdowns, except some meat packing plants that were becoming hot spots, no mandatory masks. Just a steady downward trend since mid to late April, and that was after being ridiculed for having one of the biggest "hot spots" in the country.
As a comparison to a geographically and populationally similar state, North Dakota issued shut down mandates for over a month and a half, and had reopened in stages through June. And they are experiencing a spike like most of the rest of the country. Their numbers are way higher now than when they started the shutdown to begin with.
South Dakota seems to have had the least impactful shutdown mandates, and their cases have been steadily declining with no huge spike ever, just a couple of anomalous daily spikes. Wyoming is another state that had minimal shutdown orders, and, though their cases have been on steady upward trajectory, they aren't experiencing the same sort of spike like everyone else.
California, Oregon and Washington have been pretty much lock step in their response, and are pretty much lock step in the results. Relatively low cases, shut down, reopen, spike.
Massachusetts appears to have spiked during their shutdown, and has had maybe a slight upward trend after a massive drop off. New York is the same and a few other New England States are about the same. I haven't pinpointed which New England states are responsible for the current regional spike, though.
If I had time, I would like to dig into this more. The trend I can try to start to put together is that either shutting down may have been justified in high population density areas that were being hit hard, or the shutdowns may not have done anything, the virus ran its course, and now the numbers are down and staying steady in those areas.
It could be that states that chose to shut down without the numbers to justify it are now dealing with the consequences. I've seen claims of herd immunity kicking in at as low as 10-20% for Covid. That could be why the places that were hit the hardest have dropped and stabilized, and those that weren't are now being hit hard, and will drop and stabilize. It may be too soon to tell, but the nationwide trend does seem to have reached a tipping point. Let's hope it keeps going down and stabilizes at low levels everywhere.