Donald Trump's attacks on the media have brought us to a dangerous moment in US politics

It appears to be the return of domestic political terror not seen since the 1970s, when ultra-radical groups were at large. They were on the far left; now we have terror emerging, apparently, from the far right

Even for the king of chutzpah, it takes some presidential-sized brass neck to make a speech partially blaming the wave of pipe bombs sent to Democrats and the CNN on media “hostility” to his policies. Obviously Donald Trump isn’t going to take any of the fair share of the blame for coarsening public discourse, for using violent language and for treating political opponents and journalists alike as crooks, frauds or both. That would be asking rather too much of this vain, brittle personality.

Still, while some way short of the level of humility that would be appropriate in the circumstances, at least President Trump acknowledged what was happening in America.

In remarks that were tellingly scripted rather than impromptu, Mr Trump made some statesmanlike noises: “Any acts or threats of political violence are an attack on our democracy itself. We want all sides to come together in peace and harmony. Those engaged in the political arena must stop treating political opponents as morally defective.”

He cannot be faulted there. Yet, of course, he could not help himself from adding some bogus moral equivalence of his own, adding the rider that the media has “a responsibility to set a civil tone and to stop the endless hostility and constant negative and oftentimes false attacks and stories”. That, of course, is itself a false accusation, and the kind of remark that has brought America to this point.

Later, left alone with his smartphone, Mr Trump reverted to type again: “A very big part of the Anger we see today in our society is caused by the purposely false and inaccurate reporting… Mainstream Media must clean up its act, FAST!”

At least some are brave enough to point the finger. James O’Neill, the New York police commissioner, says that the recipients may have been selected because of their opposition to Trump. “It is of concern to us,” Mr O’Neill said. A valuable intervention.

It is, as they say, “a moment”, and a dangerous one. It appears to be the return of domestic political terror not seen since the 1970s, when ultra-radical groups such as the Symbionese Liberation Army, the Black Panthers and the weathermen were at large. They were on the far left; now we have terror emerging, apparently, from the far right. It is no coincidence that it has done so as deep divisions in American society have opened up, with nationalism on the rise. As the action of neo-Nazis and racists at rallies demonstrates, there is a violent impulse that often attends such political action. Consciously or not, they feel validated and emboldened by the rise of Trump, his attitudes, his blind nationalism and his disdain for the usual democratic mores.

Were it not for alert Secret Service officers, America would today be mourning the loss through assassination of one of its major public figures, as it has so often and so traumatically in previous ages. Hillary Clinton, Barack Obama, Joe Biden – all might have been victim to a terrorist bomb. It seems unlikely, given the ugly political mood prevailing in the United States, as well as the ready availability of firearms and the precursors for improvised explosive devices, that this will be the last we hear of such attacks. One day the terrorists may get lucky, and America will, more even than now, need a leader who can unite an anxious nation. It won’t be the current occupant of the White House.