Yesterday’s Sunday Times (£) interview with Theresa May was a reminder that there have been three in her marriage from the start: herself, Philip May – and the Conservative Party.  They have never known each other outside that context, having first met as Tory activists at Oxford.  The security they have is rooted in it.  This has consequences.  When the Prime Minister came to ConservativeHome’s reception at this year’s Party Conference, I was struck by how she didn’t simply sweep in, make her speech, and leave.  Instead, she lingered, working the crowd, gladhanding people.  With her well-worked sense of duty, she would doubtless have done so anyway.  But she gave every sign of enjoying it, and why wouldn’t she?  After all, her successful career and happy marriage have both grown out of her life as a member.

There are no counter-factuals in marriage or anything else, but one can’t help thinking about them.  May’s reshuffle balanced a recognition of experience (David Davis, Michael Fallon) and feeling for party service (David Lidington, David Gauke) with promoting some old allies from those Oxford days (Damian Green, Alan Duncan).  Her repect for the Party’s culture has been demonstrated by her lack of enthusiasm for Multi-Constituency Associations, and by her return to the Whips’ Office of some of the scope for ministerial appointments.  The Conservative Party, like the Church of England, is so integral to her world that she may not imagine life without either.  I can’t help wondering if this sense would be as strong if she had married someone outside politics altogether.

When they were together at Oxford, he was President of the Union – and it was he, not she, who was more often spoken of as a future Prime Minister.  His voice is clearly the one that sways her most.  This has not always been so for recent Conservative leaders.  I doubt whether Betsy Duncan Smith or Sandra Howard ever swayed a purely political decision that either Iain Duncan Smith or Michael Howard made.  Ffion Hague may have had some influence over William Hague in matters affecting Wales when he served as Welsh Secretary, but surely not otherwise.  But there seems to be one very recent exception to the rule – Samantha Cameron, the opposite of Philip May in that she isn’t a creature of the Party.

For though her background is institutionally Tory – her father is a former Conservative councillor (and a baronet) and a grandmother was once married to a former Conservative MP – her own take on life has a freewheeling streak.  A friend describes her as Francis Elliott and James Hanning’s early biography of David Cameron as “a hippy at heart” – who when at university, according to the book, “seems to have immersed herself in some of the wilder shores of Bristol life”.  None of this is an impediment to voting Conservative – Ed Vaizey once apologised after suggesting she had done otherwise – and, after all, she is a businesswoman.  But it is hard to imagine the lady with a dolphin tatooed on her ankle settling down each morning to read the Daily Mail.

One Cabinet Minister of the time claimed that she was the driving force behind her husband’s support for same sex marriage.  This is very unlikely.  But the Camerons’ marriage is a partnership of equals between people who each have their own career.  Had the uxorious former Prime Minister settled down with someone a bit more, well, tweedy, it follows that more tweedy views would have knocked around the Cameron home.  That might have made a difference to the way the former Prime Minister, say, ran his modernisation campaign – or the EU referendum.  At any rate, Samantha Cameron has been cited as the original source for a Cameron slogan: “There is such a thing as society, it’s just not the same thing as the state”.

The power of the political spouse isn’t confined to those of party leaders.  Indeed, Michael Gove’s perhaps did more to put Theresa May in place than did the latter’s own husband.  There is something in George Osborne’s mischievous description of Vine’s famous despatch to her husband: “in a single email of only a few sentences, Sarah succeeded in switching the support of the Daily Mail, losing the support of Rupert Murdoch, destroying the leadership campaign of Boris Johnson, preparing the way for Theresa May…beginning the leadership campaign of Michael Gove and ending the leadership campaign of Michael Gove”. However, Tim Shipman’s authoritative All Out War makes it clear that Vine only came round late to the view that her husband should stand himself.

Another wife of a leading Conservative politician played an even bigger part in getting May into Downing Street, simply by her contribution to prising David Cameron out of it.  Boris Johnson’s motives in coming out for Leave have ceaselessly been pulled around and about.  One school of thought stresses his leadership ambitions.  Another one points instead to his years of columns hostile to the EU.  But I think that most of the commentary, my own included, understated a domestic influence.  Marina Wheeler, a.k.a Mrs Boris Johnson, is a QC with well-developed views about the European Court of Justice: writing in the Spectator after Cameron’s deal but before the referendum, she said that “the status quo is untenable”.  Her low opinion of the renegotiation will have had an impact on the man who is now Foreign Secretary.

Philip May, Samantha Cameron, Sarah Vine, Marina Wheeler – all married people who became Conservative MPs; all are Tories themselves, of one sort of another; all have influence, or have had.  They have their equivalents on the other side of the political fence.  Perhaps one of the Labour blogs will list them, though they will presumably exempt the wife of the Party’s greatest Prime Minister to date.  Violet Attlee was a devoted wife to Clement, driving him around during his later election campaigns.  She was also, it seems, a lifelong Tory voter.