“THERE’S frankly no need for a special prosecutor,” the White House spokesman, Sean Spicer, told journalists on May 15th. He was responding to concerns about the independence of investigations into Russia’s efforts to influence the election last November, with alleged assistance from members of Donald Trump’s campaign team. Yet on May 17th the Justice Department announced that it had exercised its prerogative to appoint just such an independent investigator. The main Russia probe, run by the FBI, will be handed to a respected former FBI director, Robert Mueller (pictured), in the role of special counsel. He will be empowered to run the investigation, and press charges, as he sees fit.

This is a terrible blow for Mr Trump. The president has said Russian spies did not meddle in the election, though America’s intelligence agencies say they did, and that there was no collusion between his advisers and the Russians. He has called the FBI investigation a “taxpayer-funded charade”. He has also been accused of trying to influence it. On May 16th the New York Times reported that the president had advised his then FBI director, James Comey, to lay off Michael Flynn, the former national security adviser, after sacking him for having surreptitious conversations with Russia’s ambassador and lying about them. The investigation Mr Trump has thus sought to rubbish and perhaps divert will now be formidable. Even if he has nothing to hide from it, this is deeply humiliating.

Mr Mueller, who ran the FBI for 12 years until 2013, having been hired by George W. Bush and retained by Barack Obama, is admired by both parties. He will be free to redesign and run the FBI probe, and will have ample resources to do so. In theory, he will be answerable to Jeff Sessions, the attorney-general, yet the fact that Mr Sessions has recused himself from playing any role in the Russian investigation—after he was also revealed to have kept weirdly shtum about meetings with the same Russian diplomat, Sergey Kislyak—is an additional guarantee of Mr Mueller’s independence. For the same reason, the decision to appoint Mr Mueller was taken not by Mr Sessions, a Trump loyalist, but by his deputy, Rod Rosenstein. The White House was not informed of this development until just before it was made public.

Mr Rosenstein’s decision is a clear victory for America’s checks and balances. But Mr Trump and his advisers should blame themselves, not the system, for this. By hiring Mr Flynn, despite multiple indications that he was unfit for a senior government position, Mr Trump ensured his fledgling administration became instantly embroiled in a new round of Russia-related scandal. Because he failed to disclose his meetings with Mr Kislyak, Mr Sessions was forced to cede control of the FBI investigation to Mr Rosenstein. By allegedly leaning on Mr Comey—“I hope you can let this go,” the president is reported to have told him, in reference to Mr Flynn’s misdemeanour—and then, on May 9th, sacking him, Mr Trump may have blundered most seriously of all, in sight of an assiduous witness. Mr Comey is reported to have kept a careful record of all his chats with the president.

As they contemplate the gravity of Mr Trump’s troubles, even Republicans are tempted to recall the last time a Republican president was disgraced and chased from office. The president’s scandals are of a “Watergate size and scale”, said Senator John McCain of Arizona. Yet there is a big difference between Richard Nixon’s disgrace and fall in 1973-74 and now, which makes it all but certain that Mr Trump is in no danger of imminent impeachment. Then, the Democrats controlled Congress, wherein lies the power to impeach. Now, the Republicans do—and no Congress has ever moved to dislodge a president of the same party as its majority tribe. Sure enough, despite the more anxious comments being made about Mr Trump by a dozen or so Republicans, including Mr McCain, most are silent.

Electoral logic explains that. Though Mr Trump has the worst ratings of any new president on record—less than 40% of Americans approve of him—most Republican voters are still with him. With a nervous eye to the mid-term elections due next year, most Republicans therefore consider attacking the president to be electorally suicidal.

This may change. If Mr Mueller turns up something seriously incriminating for the president, even the most timorous Republicans may abandon him. If the Democrats capture the House of Representatives next year, as they may, it is also likely that they would vote to impeach Mr Trump; though he would in that case probably be saved by the Senate, as Bill Clinton was in 1999. In the meantime, however, a likelier outcome of his rule-breaking is less dramatic, but nonetheless horrendous for America.

With Congress descending into partisan rowing about Mr Trump, there is already little prospect of Democrats and Republicans co-operating on legislation. There is at best a vanishing prospect of Republican congressmen, who no longer fear the president as they once did even if they will not condemn him, co-operating among themselves to carry through his agenda. Instead of remaking America with bold initiatives, Mr Trump faces a prospect of doing little of anything. The S&P500 fell by almost 2% on May 17th as investors mulled that dismally familiar prospect.

The dismay Americans felt at their governing system’s previous round of tribalism and dysfunction fuelled the rise of Mr Trump. There is no reason to suppose this cycle will lead to anything better.