It is at this point a constitutional crisis would erupt. America’s founding fathers created a system based on laws, not men. But it is down to people to uphold the system. In theory, there is nothing stopping Mr Trump from doing whatever he likes. Most constitutional lawyers say you cannot indict a sitting president — even if he has repeatedly obstructed justice. If Mr Mueller were sacked, in other words, no court would reinstate him. The same applies to Mr Sessions, and as far down the chain as Mr Trump cared to go.
The US republic’s ultimate safety net is public opinion. So far most Americans are not inflamed by the Russia investigations. It is hard to blame them. People in Washington are obsessed by the day-by-day dramatic twists. But most ordinary Americans lack the time to absorb the endless waves of detail. Who cares if Mr Sessions held undeclared meetings with the Russian ambassador during the campaign? Politics is a dirty game and the people who throw mud are usually covered in it themselves.