President Donald Trump has been desperate to fire Deputy Attorney General Rod Rosenstein and squeeze the Mueller investigation. (Trump’s accomplices in congress even tried to impeach him.)

Now, it looks like somebody in the administration or in Congress is leaking stories mischaracterizing a sarcastic comment, originally suggested by someone else, to give Trump a convenient pretext to fire him.

Rosenstein’s removal would be a major blow against the Mueller investigation.

• Rosenstein is Special Counsel Robert Mueller’s boss; he authorized Mueller’s investigation and controls its budget.
• He’s been one of the few people in the administration to stand up to congressional Republican bullying, pushing back against some of the most blatant attempts to undermine Mueller and mislead the public.
• If Trump replaces Rosenstein with a loyalist—which he’s been privately saying he’ll do for months—they could effectively smother Mueller’s ongoing attempts to expose the truth without ever having to fire the special counsel.

Trump and his accomplices are actively seeking to obstruct justice and end the Mueller investigation.

• Rosenstein is not some partisan opponent of the president; he’s a Republican who Trump himself appointed. But he appointed Mueller and has backed the Russia investigation, so he became one of congressional Republicans’ favorite punching bags.

The walls are closing in on Trump and he is now desperate to stop the investigation. Members of Trump’s inner circle, including his longtime attorney Michael Cohen and his campaign chairman Paul Manafort, are telling Mueller what they know about the campaign’s collusion with Russia—when suddenly somebody gave Trump perfect cover to stop the probe.

Any unwarranted dismissal of Rosenstein would have been obstruction of justice even before this leak, but if this information was deliberately leaked to give a pretext for firing him, that could expand the obstruction of justice probe even further.