In our time, women have been gaining political power as never before. There are (by my count) 17 female presidents and prime ministers around the world today. Sixty-three of the world's countries have now had at least one female head of government or state in the past half-century.

But it's not the fact of their being female that is important so much as the feminine style today's female leaders have brought to politics. The powerful women of the 1970s and 1980s - Indira Gandhi, Golda Meir, Margaret Thatcher - were iron ladies, famous (metaphorically speaking) for having more cojones than the average male politician. By contrast, the female leaders of our time are not just female; they are also feminine. The archetype is German Chancellor Angela Merkel.

Now when a man seeks to sum up feminine qualities, he is almost certain to be accused of sexism, so please read this trigger warning before you step any further out of your own personal safe space. I am a fully paid-up feminist. I believe in the equality of the sexes. But I do not believe in the identity of the sexes. And what I am about to say on this subject is not based on prejudice but on half a century of research.

What I have noticed is that, compared with me and my male relatives, my grandmothers, mother, sister, daughter, ex-wife and wife share or shared the following traits. They talk a lot more before arriving at decisions. They are mostly better at doing many different things at once. They are slightly less inclined to lose their tempers and much less inclined to break things. They have multiple handbags, the cluttered contents of which often seem as puzzling to them as they are to me.

Not all feminine traits translate into the realm of politics but these do. Thus Dr Merkel's political style combines the gift of the gab, multitasking, never losing her cool and a certain amount of tactical clutter.

European and Turkish leaders spent last week wrangling over a plan devised by Dr Merkel to solve the movement of mainly Muslim migrants through Turkey into Greece and on to the rest of Europe. This is the kind of negotiation she relishes. The final round, she said on Friday, would be "anything but easy". You can almost see the thin-lipped smile at the prospect of yet another 3am deal. If ever a leader preferred jaw-jaw to war-war, it is "Mutti" (Mummy) Merkel.

But now ask yourself how Europe got into this mess. On German television last July, Dr Merkel reduced a young Palestinian refugee to tears by explaining that her family might have to face deportation. "There are thousands and thousands of people in Palestinian refugee camps," she said. "If we now say, 'you can all come'... we just cannot manage that."

The waterworks worked. Six weeks later, Dr Merkel had opened the gates of Germany and was declaring: "We can manage that." All kinds of historical explanations have been offered for her epoch- making change of mind, but to me, it was the essence of feminine politics. Faced with teenager Reem Sahwil's tears, the Chancellor's reaction was an impulsive attempt to comfort her, followed by a massive and unilateral U-turn.

Likewise, all kinds of historical explanations have been offered for the rise of Mr Donald Trump but I now see a simpler one. He is just the latest standard-bearer of a worldwide revolt against feminine politics. Leave aside terms such as populism and fascism: This is caveman politics - not just male but aggressively, crassly masculine. Mr Vladimir Putin is the Russian version. Mr Narendra Modi is the Indian version. Mr Xi Jinping is China's macho man. Mr Recep Tayyip Erdogan is Turkey's. They talk tough. They strike tough poses. They would never, ever comfort a crying girl. On Wall Street, in the days when the recently deceased John Gutfreund was running the Salomon Brothers investment bank, there was a crude term for such men. They were known as BSDs: big swinging dicks.

"What you find with Donald Trump is he's a counterpuncher," explained Mr Trump's campaign manager Corey Lewandowski, . "Someone punches him and he punches back, and he punches back much harder."

When Mr Trump said that Mrs Hillary Clinton got "schlonged" by Mr Barack Obama in the 2008 primaries, she accused him of having "a penchant for sexism". Mr Trump shot back that her own husband had scarcely been a role model. In the words of Mr Lewandowski: "He punched back at her 10 times harder."

This crude fighting talk is the essence of anti-feminine politics. Recently, rhetorical violence turned to actual violence at a series of Trump rallies. You cannot imagine anyone throwing last week's sucker punch during a Merkel speech. Nor can you imagine Mrs Clinton threatening "riots" if denied the Democratic nomination. She wants to "make America whole again" - a classic feminine slogan - not to punch a hole in America.

Note, too, that the BSDs are repudiating not just female leaders but also the "girlie men" leaders of the post-Cold War era who were very young, went to the gym, sipped pinot noir and had metrosexual policies to match. Politics, like the German language, has masculine, feminine and neuter.

The big question now is whether or not macho politics can take "the Donald" all the way to the White House. Pundits and bookmakers expect him to lose, partly because even more people disapprove of him (60 per cent) than disapprove of Mrs Clinton (53 per cent), partly because Mr Trump appears to have alienated every constituency except white non-Hispanic males without college degrees.

I hope that is right, but - having badly underestimated Mr Trump before the primary season began - I would not bet my life on it. Hearing Mrs Clinton's Dalek-like utterances after her victories over Mr Bernie Sanders on Tuesday, I began to doubt her ability to keep the coalition of white liberals and minorities that elected Mr Obama twice.

The tragedy is that, compared with the male politicians of an earlier generation, today's macho politicians are not truly manly at all.

Last week, I sat down to talk with Mr George Shultz, the former secretary of state and my most illustrious colleague at Stanford University's Hoover Institution. He told me the first lesson he learnt at US Marine Corps boot camp: "This is your rifle. It will be your best friend. Look after it. And never point it at anyone unless you are willing to fire it."

True, Mr Trump was sent to a military school (after all other educational options had failed). But, unlike Mr Shultz, he has never seen action. Indeed, he has served his country less to date than the lowliest grunt. In that sense, there is something deeply phoney about his machismo. A man who has to reassure the world about the size of his genitals is not macho; he is just a boor who doth protest too much.

The good news is that a new generation is on its way: Americans who served their country in Afghanistan and Iraq, a remarkable number of whom are now going into public life, seeking and winning election into state legislatures and Congress. Quite a few of this generation are in fact women. I just hope they turn out to be iron ladies.

THE SUNDAY TIMES, LONDON

• The writer is Laurence A. Tisch professor of history at Harvard and a senior fellow of the Hoover Institution, Stanford.