Why is there so little doubt about the motive? Sessions was one of Trump’s earliest supporters, continues to share his views on everything from immigration to refugee policy to voting rights to police shootings, and differed significantly only on whether he should’ve recused himself from the probe into foreign election interference.

Trump has obsessed about that recusal for months, behind the scenes and in public, stating in August, “Even my enemies say that Jeff Sessions should have told you that he was going to recuse himself and then you wouldn’t have put him in.” More generally, Trump has suggested that an attorney general ought to loyally protect even a lawbreaking president from the legal consequences of his unlawful actions—and Politico reports that his own son now expects to be indicted.

Wednesday’s ouster will put the Mueller probe under the control of new Acting Attorney General Matthew Whitaker, the author of a 2017 CNN article arguing that Mueller “has come to a red line in the Russia 2016 election-meddling investigation that he is dangerously close to crossing.”

Whitaker reasoned in the article that investigating Trump’s finances “falls completely outside of the realm of his 2016 campaign and allegations that the campaign coordinated with the Russian government or anyone else,” even though Trump Organization finances and business relationships could be relevant if they gave the Russian government leverage over the president, his children, or his associates—or if Trump sought to coordinate with Russia in the realm of politics with the expectation that doing so would benefit his businesses.

Adam Serwer: Trump will only get more dangerous.

In another article, Whitaker argued that Trump was correct to fire James Comey, that “calls for an independent counsel or commission to investigate allegations that Russia tried to interfere with our elections ring hollow when similar calls for special counsels during the scandals of the Obama administration were dismissed,” and that “hollow calls for independent prosecutors are just craven attempts to score cheap political points and serve the public in no measurable way.”

And he has tweeted about the probe, criticizing the raid of Paul Manafort’s house and sharing an article that referred to “the Mueller lynch mob.”

Trump “told advisers that Whitaker is loyal and would not have recused himself from the investigation,” according to The Washington Post. But analysts at Lawfare say Whitaker is obligated to seek the advice of Justice Department bureaucrats about the necessity of recusal:

The relevant Justice Department guideline is Section 45.2 of Title 28 of the Code of Federal Regulations, which states that “no employee shall participate in a criminal investigation or prosecution if he has a personal or political relationship with” either “any person or organization substantially involved in the conduct that is the subject of the investigation or prosecution” or “any person or organization which he knows has a specific and substantial interest that would be directly affected by the outcome of the investigation or prosecution.” Although the regulations do not indicate that Whitaker’s public statements alone necessarily require recusal, Whitaker has other connections to people whose conduct is at issue in the matter. For instance, the regulations define a political relationship as “a close identification with an elected official, a candidate (whether or not successful) for elective, public office, a political party, or a campaign organization, arising from service as a principal adviser thereto or a principal official thereof.” Rebecca Ballhaus of the Wall Street Journal reports that Whitaker chaired the 2014 Iowa state treasurer campaign of Sam Clovis, who went on to serve in the Trump campaign and administration and who, Ballhaus notes, is now a grand jury witness in the Mueller investigation. The Des Moines Register reported Whitaker’s chairmanship of Clovis’s campaign during the campaign itself. What’s more, in a text message to Ballhaus after Whitaker’s appointment, Clovis wrote that he was “proud of my friend,” referring to Whitaker, raising the question of whether there is a personal relationship as well. There is an important process point here: Under the same Justice Department regulation mentioned above, Whitaker is obligated to seek guidance from career ethics attorneys regarding whether he should recuse. This is the process Jeff Sessions used in determining that the rules required that he recuse, and Deputy Attorney General Rod Rosenstein also sought guidance regarding his obligations, though Justice officials determined that his recusal was not required. If Whitaker either does not obtain an ethics opinion from career officials or if he departs from that guidance, that would be a serious red flag.

Will Republicans protect the Mueller investigation as Trump gains new visibility into what the special counsel has been up to all this time?