The problem Boris Johnson faces over the Dominic Cummings affair right now is a problem of perception. Is there one set of rules for the ruling elite, and another for everyone else?
Can known carriers of the virus make an 800km round trip (and possibly a 100km trip to a tourist spot as well), and get away with it because they are friends of the prime minster?
So far Mr Johnson has made a case for his chief adviser on fairly narrow legal grounds; Dominic Cummings did not break the law as it was then in force, nor did he breach the guidelines that were then in force, and used common sense in making his decision, as the government says it wants people to do.