Washington has been plunged into institutional crisis

Let me be very, very careful: America is a stable nation with institutional safeguards and the rule of law woven into its society.

Government agencies and departments are run by some of the smartest professionals in the world.

That said, overnight a febrile atmosphere has developed that challenges some very basic assumptions.

Firstly, the Department of Justice has been plunged into crisis.

The acting Attorney General, Sally Yates, last night defied the President's Executive Order on the travel ban - telling her department not to defend it in court - and was promptly fired by the White House.

It was quickly dubbed the Monday Night Massacre.

Secondly, the acting Director of the Immigration and Customs Enforcement, ICE, has been replaced without explanation.

Thirdly, and in my view most significantly, a letter has been published that appears to be close to a call for a mutiny within the machinery of government.

This has been signed by one hundred pre-eminent former government and national security officials.

It is essential reading for the extraordinary breadth of its criticism of the President and his actions, and for the suggestion of open defiance.

Eleven days into this Presidency and Washington has been plunged into an institutional crisis.

We knew Trump would disrupt this town. But this is different. This feels more like a meltdown.

So - and I never thought I would write this about the United States - the government is actually feeling unstable in a very un-American sort of way.

Into this volatile mix comes another decision guaranteed to further escalate political tensions.

Tonight President Trump names his nominee for the Supreme Court.

I don't know where this ends. But I have friends in the upper reaches of government who couldn't sleep last night, and who were pacing up and down, stunned at where America finds itself.