Firing Mueller is a terrible idea. Trump might just do it anyway.
If he sacks the special counsel, the ensuing scandal would consume Congress
One of the big reasons why the scandal surrounding President Trump and the FBI's investigation into Russian interference in last year's election is accelerating so quickly is that people at its center don't understand the consequences of their words and actions. Generally speaking, when you're facing a Department of Justice inquiry the smart thing to do is keep your mouth shut and let your lawyers handle all the talking. Donald Trump, however, is using his Twitter platform to disparage the Russia investigation, attack the people running it, and expose himself to still more jeopardy.
On June 15, the president tweeted that the whole inquiry into potential collusion between his 2016 campaign and the Russians was "phony" and he appeared to confirm The Washington Post's scoop that Special Counsel Robert Mueller had expanded the investigation to look at whether Trump had obstructed justice by firing former FBI Director James Comey. The morning after, Trump attacked Mueller's DOJ supervisor, Deputy Attorney General Rod Rosenstein, and disparaged Mueller's investigation as a witch hunt:
Last week I wrote that the biggest danger Trump faces from the special counsel investigation is not the obstruction probe, but Mueller's digging into the finances of Trump's associates. Tweets like these, however, indicate that Trump is massively frustrated and wants to get rid of Rosenstein, Mueller, and the Russia investigation altogether. Trump has apparently already been talked out of firing Mueller once, but if the president changes his mind and tries to remove the special counsel, he'll create an immediate and dire political crisis from which he'd be lucky to emerge.
Right now there is no substantive, legitimate argument for having Mueller fired. The reasons behind Trump's annoyance with the special counsel investigation are entirely political: He's hypersensitive to questions surrounding his legitimacy, he chafes at the idea that his authority could be questioned, and he mocks the entire Russia investigation as Democratic sour grapes. A few of Trump's toadies and allies in the conservative media have tried to argue that Mueller is some sort of "deep state" hatchet man, but Trump would need better justification for firing the special counsel than a Newt Gingrich conspiracy theory.
Were Trump to go through with it anyway, it would be the most politically self-destructive act of his young presidency. Trump already fired James Comey and admitted on national television that the Russia investigation influenced his decision, which is why he's reportedly facing an obstruction of justice probe. It's difficult to think of something more self-incriminating than the president firing the person investigating him for obstruction.
Democrats would explode and draw obvious comparisons to the 1973 Saturday Night Massacre, in which Richard Nixon fired the independent prosecutor investigating Watergate. But, more importantly, Trump would be causing a massive political headache for his Republican supporters in Congress.
Most Republicans were happy to see Mueller take over the investigation after Comey was fired because it allowed them to redirect politically fraught questions about Russia to the special counsel's office. And a number of Trump's key allies have already vouched for Mueller's integrity. House Speaker Paul Ryan said the special counsel should be allowed to "do his job" and that "the best vindication for the president is to let this investigation to go on independently and thoroughly." Basically, Republicans want the Russia issue to be handled by Mueller so they can work on other things, like repealing ObamaCare and cutting rich people's taxes.
If Trump fires Mueller, the ensuing scandal will consume Congress. Republicans in the legislature have thus far been determinedly supine in the face of Trump's abuses of authority, but firing Mueller would be a far more flagrant and dangerous misuse of executive power than anything we've seen to date. Republicans would be asked about impeachment and they would struggle to justify Trump's actions. The Department of Justice would be hopelessly compromised by the White House's political agenda, which would put massive pressure on the House and Senate committees conducting parallel investigations of Russian interference in the 2016 election.
The promise of crippling scandal and controversy is, of course, no guarantee that the president won't go ahead and get rid of Robert Mueller. Trump has only shown less caution as the stakes of the Russia probe have gotten higher for him. Right now the issue is just festering as Trump vents and Mueller moves ahead with his work. If Trump and his attorneys had any instinct for self-preservation, they'd just clam up and let the investigation proceed. Instead, the president is goading himself into committing an impeachable offense.