The US, with its federal system of government, provides 50 experiments, because the individual states vary in size, age profile, population density and in their response to pandemic.The surge began at the start of June, shortly after the Memorial Day holiday on 25 May showed the same sort of flouting social-distancing protocol as seen in Bournemouth last week.The sharpest increases in cases have been seen in the south and west, and one hypothesis worth testing is whether there is a link between those states that eased restrictions fastest and those seeing an increase in infection rates.As research by the US financial firm Jefferies has shown, in states such as Arizona, Texas and Utah, where the number of cases is rising exponentially, activity is starting to contract. State by state comparisons of Google data, which tracks visits to retail and recreation establishments, show states where the virus is spreading are performing markedly worse than the rest of the country.What’s more, Americans understood the difference because the loss of momentum was concentrated in states where a rising caseload could not be put down to testing. When the two countries went their separate ways at the start of the crisis, the assumption was that Sweden would have more deaths but suffer less damage to its economy. No, because while the majority of people will act prudently without being forced to do so in order to avoid catching the virus a minority will refuse to change their habits. The experience of New York state suggests that a tough lockdown reduces the risk of a second wave and makes it easier for life to return to normal.