Washington is weary of the drama. More than weary. Emotionally exhausted. The city feels like it's living through a blend of TV shows - House of Cards, The Apprentice and Homeland - but this time it is a real-life political thriller.

And overnight we have a new twist that seems barely credible. It is so potentially explosive, in fact, that the I-word - Impeachment - is being openly discussed on the TV networks.

Donald Trump has already warned his fired FBI Director not to leak any information against him. The threat was clear. The White House may have secret tape recordings to discredit James Comey.

Well, that tactic has now backfired spectacularly.

Last night James Comey went into battle against the President, even if by proxy. The message from Comey to Trump is, in effect, this: You may have tapes but I've got detailed notes of every encounter I've ever had with you.Which are more credible? Trump's secret tapes - if they exist - or Comey's written memoranda?

The first of these memos was leaked last night to the New York Times. It makes the damaging claim that Trump - having cleared the Oval Office of all other staff - told the FBI Director in February not to pursue the Flynn investigation. (Mike Flynn was the National Security Adviser being probed for links to Russia).

According to the Comey memo, Trump said: “I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go.”

Michael Flynn, pictured above left with Donald Trump, was ousted as national security adviser in February. Credit: AP

To many in this town - perhaps to most, even to Republican loyalists - this smells of obstruction of justice.

And since we're at a seemingly Nixonian moment, a Presidential historian last night helpfully tweeted out this reminder:

Donald Trump hit back at his critics tonight in a speech at the coastguard graduation ceremony, saying "no politician in history has been treated worse or more unfairly".

No one can know where this goes next. But Comey's FBI memos are government property, not his personal correspondence. So they will come out. Congress is already demanding to see them. The FBI was told last night to preserve all relevant documents.

So we are now at a pivotal moment, while we wait for the contents of the Comey memos. The survival of the Trump Presidency may depend on what they reveal.