One. Looks.
Fat and flamboyant, Boris Johnson and Donald Trump are alike well known for their blond locks which are of the type that used to be described in shampoo adverts as 'unmanageable'. Just like both of them.
Two. Smugness.
Born into wealth and privilege, both of these men have been surrounded from birth by devoted families who have added to their sense of self worth. Far from suffering from the modern malaise of low self esteem they appear to have the opposite problem. They both seem to have come to the conclusion that their good fortune is not the result principally of chance, but that these richly-deserved rewards have been bestowed on them by the gods because of their brilliance.
Three. Ego-driven politics.
For a long time, I had a theory that Trump had no intention of actually winning the Republican nomination. It seemed to me that he was doing the whole thing for publicity - his brand is all he has basically - but that he didn't actually have the hard cash to fund a run for the White House. As in the movie 'The Producers', I saw him with his advisers certain that he had come up with a new statement that would put him safely to the back of the pack. "I've got it!"
But then, to his chagrin, each new outrage has only added to his support. It's all gone a bit too far now, and I am starting to think he means it. But I still feel that his principal concern is not how he can serve his country, but what's in this for Donald J. Trump.
Equally with Alexander Boris de Pfeffel Johnson, there seems to be a political calculation behind him coming out against remaining in the EU which is that he will be the only serious candidate for the next leadership of the Conservative Party who is on the 'Out' side. He was always going to be an 'Outie' but he made a great play of waiting for the deal and agonising over his decision before rattling out a text to the PM, minutes before his press conference. It was a pantomime.
Boris has always been destined for greatness, in his own eyes at least. Thus far it has not properly mantled around his shoulders. 'Boris Bikes' forsooth, are hardly the stuff of legend. A lively and colourful character who adds to the gaiety of the public stage, he has been a popular Mayor of London and has written a readable biography of his hero Winston Churchill. These are no mean achievements. But he wants more. However Boris is possibly more Falstaff than Henry IV.
Four. Nostalgia
Both Trump and Johnson base their current campaigns on a hankering over past glories.
Trump's main promise to the American people is that he will "make America great again." He promises to return the USA to a mythologised past in which American companies and American citizens are protected from the effects of globalisation. Locked down borders, protectionism in business. (Unusually for a Republican, he opposes US free trade agreements with China.) But ironically, there would be no clearer sign of a once-great country in decline than the election of such a backward-looking leader. Harking back to the past and fearing to embrace the challenges and opportunities of the future isn't likely to work that well in practice.
Ironically, given his position on Europe, Johnson is related to lots of European royal families. Growing up he was fed stories of the past glories of the de Pfeffers and confided to the BBC his memories of the locked chest of family silver which his relatives carted round the place for half a century.
His main opposition to the EU is not based on the fear of free movement of labour, although he is happy to have the support of economically marginalised voters who see it as a threat.
He is the effective leader of the faction who see the Europe Union as a threat to the sovereignty and democratic traditions of Great Britain. He doesn't see a future in which sovereignty must be shared and where Britain has to work in partnership with the other democratic nations of Europe.
At bottom, he would like to see Great Britain's Imperial Parliament calling the shots as it once did, when half the globe was coloured pink. Like his associate Michael Gove who as Education Secretary pontificated about reintroducing the "Our Island Story" version of British history, Johnson's dubious politics are based on nostalgia for the Empire.
Five. Impending Failure
Any major political party has to be effectively a coalition between different factions. It is sometimes the case that a particular faction is strong enough to impose a leader on the whole party. That is what happened with Jeremy Corbyn in the case of the British Labour Party.
This may be what is happening in the case of Donald Trump. The angry white voters who see their historic advantage being eroded see him as their spokesman. If, however he does gain the Republican nomination, which is still unlikely, he doesn't have a frog's chance on the motorway of being elected President of the USA. He has very little traction outside his own faction.
Equally, it may be possible that Johnson could gain the leadership of the British Conservative Party. But he could never be elected as Prime Minister of the United Kingdom.