Monday night’s US presidential debate should convince a majority of American voters that Hillary Clinton is their only credible choice for the White House. Yet it may well fail to do so, in the new era of ‘post-truth politics’. The historian Sir Michael Howard suggests that on both sides of the Atlantic, we are witnessing a retreat from reason, an attempt to reverse the onset of the 18th-century Age of the Enlightenment, which banished superstition and religious faith as a basis for reaching conclusions. The progress of Donald Trump supports his thesis. I have just spent a fortnight in southern California, researching a book on the Vietnam war, and saw everywhere manifestations of Trumpery. A big Jeep overtook me on the coastal highway, bearing a window sticker: ‘I AM A STRAIGHT CHRISTIAN CONSERVATIVE GUN-OWNER. What more can I say to piss you off?’

Cultured Americans view the Trump candidacy with almost paralysed horror. A sixty-something historian friend emailed from Washington to say that he and his wife have been discussing a move abroad if the Republican candidate wins, because ‘such a United States would not be one that we wish to be part of’. He asked: had my wife and I, as Remainers, faced a similar dilemma following Britain’s Brexit vote? I responded that we rub along fine socially with Leavers, so long as they neither wax lyrical about the glorious dawn breaking over our shores, nor insist upon speaking well of Boris Johnson.

I visited an elderly ex-soldier, who took me into his study to view some documents. Beside the computer lay a loaded pistol. Seeing me glance at it, he said a trifle apologetically, ‘This is what Americans do.’ Trump on Monday night applauded gun ownership; though Clinton deplored ‘the plague of gun violence’, she did not dare explicitly to advocate control. I have owned sporting firearms all my life, and fired more military weapons than most people. A generation ago, when home secretary Michael Howard banned handguns, I thought his measure an unacceptable constraint upon personal freedom. I have since changed my mind. Firearms are such a curse upon US society that I thank heaven British private citizens are no longer permitted to own those designed explicitly for killing people.

I drove 300 miles across western deserts to interview Doug Ramsey, a man whose Vietnam experience made him a bleak legend. Arrived in Boulder City, Nevada, around midnight, I sought the usual motel, and was dismayed to find them all full. With a sigh, I settled down to sleep in the car, only to be awakened four hours later by a flashlight in my face, three police patrol cars around mine. Long experience of American cops, fortified by awareness of recent shootings, caused me carefully to seek permission to open my door, even though I am reasonably white. ‘Have you been drinking?’ an officer demanded. I explained my predicament, and they demanded my driver’s licence ‘so we can check you’re not wanted by Interpol’. The chief cop then quizzed me: ‘This says Sir Max Hastings. You royal, or something?’ Just a British gag, I said, and escaped a vagrancy charge. As I sat outside a diner, reading Trollope on a Kindle during the interminable wait until opening time, I reflected ruefully that I am getting too old for such nights as that.

Doug Ramsey was a US foreign service officer who in January 1966 fell prey to a Vietcong ambush while delivering aid supplies. He spent the next seven years as a prisoner in the jungle, mostly in solitary confinement, sometimes in a bamboo cage significantly shorter than himself, which inflicted crippling injuries. Much cant is peddled on both sides of the Atlantic about our concern for ‘war heroes’. Well-meaning people cycle across continents or row the Pacific to raise money for disabled veterans. It remains nonetheless troubling how little effective help they receive. Though mentally undiminished, Ramsey is almost totally immobilised, but ineligible for the medical treatment available to ex-military personnel. He depends on Medicare and civilian compensation, and is justly bitter about their inadequacy. He says: ‘I share with disabled Vietnamese veterans an anger that both our respective governments have screwed us’.

Publication of the Yahoo traffic of some important Americans is almost certainly a Kremlin-inspired demonstration of Russian cybercraft. It impresses the US and British cryptographic intelligence communities, and may oblige those who deal in sensitive material to rethink their use of emails. All online messages, encrypted or no, are vulnerable to hackers with sufficient ingenuity and computer resources. It could prove an irony of the 21st century that old-fashioned pen and ink missives enjoy a resurgence among those who do not covet a readership in Moscow or Beijing.