It has long been known that Attorney General Jeff Sessions, much maligned and routinely ridiculed by Donald Trump, would be ousted soon after the midterm elections. But the president's decision to fire Sessions less than one full day after the end of the midterms in which Democrats seized control of the House of Representatives nevertheless comes, if not as a shock, then as a small surprise even for seasoned Trump watchers.

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It probably shouldn't, though. First, by axing Sessions with everyone else still trying to get their groggy heads around what happened in the midterms, Trump opens up a new political battlefield and deflects attention away from the elections and the Republicans' diminished Congressional power. Second, by firing Sessions quickly and boldly Trump once again made the world orbit around him — typical for a man who despises not being the center of attention. Third, by getting rid of Sessions Trump gets out of his defensive midterm election posture and on the offensive, a tactic he uses when he feels under pressure.

Russia probe under threat

To comprehend just how daring, if not reckless, Trump's action is, it is important to understand that firing Sessions was one of the few issues that both Congressional Democrats and key Congressional Republicans had repeatedly warned the president not to do. As a former senator, Sessions still has many friends in Congress, including influential Republican Senator and newfound Trump friend Lindsay Graham, who pushed Trump not to fire him. Sessions, despite his many shortcomings, was also viewed by many lawmakers as the best guarantor that the Russia probe by special counsel Robert Mueller would be conducted unimpeded by the White House.

Sessions had recused himself from overseeing the probe because of personal implications in the issue, instead assigning it to his deputy, Rod Rosenstein. More than that, Sessions had repeatedly made clear that he would not interfere in the process and that he would also not fire or reassign Rosenstein. Sessions' refusal to ax Rosenstein or cripple the Mueller probe was naturally deemed a personal affront by a president who has little interest or patience for the rule of law. Trump views everything as a potential danger, so it was always clear that Sessions had to go and that Rosenstein likely will have to follow soon.

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But we are not at that point yet. Of course it is the clear prerogative of a president to dismiss his attorney general. Trump obviously knows this and appears to bet that firing Sessions alone will not trigger enough bipartisan outrage to endanger him. He may be right. But the fact that Sessions' acting successor, Matthew Whittaker, has previously voiced strong doubts about the Mueller probe and mulled over how to hamper and slow down the investigation is alarming — and probably the reason why Trump selected him.

A challenge to Congress

Whittaker's previous musings about undermining the Mueller probe and capping its finances — views long shared by others in Trump's circle — may hint at what the White House's strategy might be. Instead of ordering Whittaker to fire Rosenstein outright and close the investigation, which likely would trigger impeachment proceedings, Trump may want Whittaker to slowly cripple the Mueller probe financially and structurally and hope he can get away with it.

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Democrats and Republicans must not let that happen. Trump, on day one after the midterms, has just issued the biggest challenge imaginable to Congressional lawmakers. It is essential for democracy and the rule of law that they answer it swiftly and decisively.