When Donald Trump set out to fire FBI Director James Comey, he first pulled in Attorney General Jefferson Sessions and Deputy AG Ron Rosenstein to create a report on how Comey had actually been too harsh to Hillary Clinton. Then, using that excuse, he dispatched his personal bodyguard with a letter to send Comey packing.

Only that’s not the way it really happened.

The special counsel, Robert S. Mueller III, has obtained a letter that President Trump and a top political aide drafted in the days before Mr. Trump fired the F.B.I. director, James B. Comey, which explains the president’s rationale for why he planned to dismiss the director.

The May letter had been met with opposition from Donald F. McGahn II, the White House counsel, who believed that some of its contents were problematic, according to interviews with a dozen administration officials and others briefed on the matter.

Before Trump pulled in Sessions and Rosenstein, he first had Statute of Liberty critic Stephen Miller draft up a letter that contained ... other reasons for dismissing Comey. Reasons that were apparently so objectionable that Trump was urged to look for a new excuse to dismiss the FBI director, no matter how ludicrous. The contents of the letter have not been made public, but the “problematic” label likely comes as a result of Trump and Miller directly attacking Comey over his failure to bend the knee and drop … that other thing.

The contents of the original letter appears to provide the clearest rationale that Mr. Trump had for firing Mr. Comey. It is unclear how much of Mr. Trump’s rationale focuses on the Russia investigation, although Mr. Trump told aides at the time he was angry that Mr. Comey refused to publicly say that Mr. Trump himself was not under investigation. 

No wonder Donald Trump’s lawyers have been writing about obstruction of justice.

Lawyers for Donald Trump have met several times with special counsel Robert Mueller in recent months and submitted memos arguing that the president didn’t obstruct justice by firing former FBI chief James Comey and calling into question Mr. Comey’s reliability as a potential witness, people familiar with the matter said.

That argument is a lot harder to make if Mueller has in his hands a vindictive letter, composed by two guys not known for their restraint, that attacks Comey over the Russia investigation or for his failure to swear fealty to Trump.