Attorney General Jeff Sessions fired Andrew McCabe as deputy FBI director Friday night, mere hours before McCabe would have earned his full retirement benefits. And President Donald Trump's tweets about McCabe's situation pretty much erase any doubts that he applied political pressure on Sessions's decision.

Trump has derided McCabe for months, even highlighting his retirement timetable three months ago.

"FBI Deputy Director Andrew McCabe is racing the clock to retire with full benefits. 90 days to go?!!!" Trump tweeted in December.

And the president tweeted again shortly after midnight Saturday morning: "Andrew McCabe FIRED, a great day for the hard working men and women of the FBI - A great day for Democracy. Sanctimonious James Comey was his boss and made McCabe look like a choirboy. He knew all about the lies and corruption going on at the highest levels of the FBI!"

It's readily apparent why getting McCabe fired might send a message that Trump likes. But might it also come back to bite Trump?

Read More: Andrew McCabe, a target of Trump's FBI scorn, fired days before retirement

Trump has now, after all, cemented the enemy status of a top-ranking official at the FBI (its No. 2) and one-time acting director. He previously did that by firing McCabe's superior, former FBI director James Comey, and Comey has rewarded that decision by leaking unhelpful things and testifying about Trump in a negative light. He is now set to release a book.

But the McCabe and Comey situations are also somewhat different. Trump arguably terminated Comey more out of fear of how he was conducting the Russia investigation; he appears to have gone after McCabe due to a vendetta and possibly to send a signal to others in law enforcement who might run afoul of him. Trump's successful push to get McCabe fired is also undeniably more personal in nature, given McCabe was ousted just 26 hours before he was to gain full retirement benefits. McCabe was already basically out the door, and firing him now - regardless of how valid the reasons in the yet-to-be-released inspector general's report - comes off as even more spiteful.

Matthew Miller, a former top Justice Department official in the Obama administration, noted that McCabe has already spoken to special counsel Robert Mueller's team, and he would have shared anything he knew about allegedly illegal actions. But Miller said that doesn't mean there isn't more McCabe might share - particularly now that he could file suit over his termination.

"There are a host of inappropriate actions by the president that don't necessarily rise to the level of criminality that McCabe may feel obliged to disclose publicly now," Miller said. "It's very much in McCabe's interests to reveal any inappropriate actions by the president that he was aware of because it helps make his case that he was fired for political reasons. He may do that in interviews, and he may do it in a lawsuit he brings over his firing."

Former federal prosecutor Patrick Cotter said McCabe would still be bound by confidentiality rules and can't share anything about grand jury testimony that he may have gleaned. But he said the treatment of McCabe is without real compare.

"I would add that for me, and I think many former law enforcement personnel, it is difficult to recall any precedent for the kind of personal vindictiveness the action by the executive exhibits towards a career FBI agent like McCabe, except from the long-time targets of federal law enforcement, like the mob or drug cartels," Cotter said. "With those criminals I noted that their hate was personal towards the agents and attorneys they thought were building cases against them. This move strikes me as very similar."

And it was made abundantly clear Friday night that McCabe is incensed by the decision. He released a lengthy statement deriding his firing as "slander" and arguing that the inspector general's report was accelerated in response to his closed-door testimony saying he would corroborate key claims made by Comey. He suggested the whole thing was part of a campaign to undermine the investigations involving Trump.

"This attack on my credibility is one part of a larger effort not just to slander me personally, but to taint the FBI, law enforcement, and intelligence professionals more generally," McCabe said. "It is part of this administration's ongoing war on the FBI and the efforts of the special counsel investigation, which continue to this day. Their persistence in this campaign only highlights the importance of the special counsel's work."

That's significantly more full-throated than even Comey was after his firing. The question now is: What does McCabe know, and how hard does he push back? We have yet to see what's in the inspector general's report, and it's quite possible that it will undercut McCabe's credibility and prove his firing was warranted. Having his name dragged through the mud could temper McCabe's public comments.

But if it doesn't, Trump and Sessions have just created a very motivated enemy.