The difficulty of Campbell-ising a politician is that you need an unexpectedly catastrophic election result - and a very short premiership. For May to become a British Kim Campbell (not a Canadian one as the title suggests!) you’d need to combine the surprise of the 2017 election with the material conditions of 2019. I’m really not sure how you get the latter into 2017, unless you meddle a lot.
My suggestion - an oldy but with a bit of colour: Michael Gove doesn’t bolt and Boris Johnson launches his campaign for Tory leader in 2016.
As polling from the time indicated, Johnson might actually have had to fight to win, unlike 2019’s virtual coronation. He emerges with a decent win but nothing spectacular (55-45, perhaps), and feels compelled to go to the country to win a proper mandate that autumn.
He’s a better campaigner than May, but the country is still reeling from the referendum and there’s a lot more visceral dislike in the country for him. Critically, it’s too early in the Brexit process for the Red Wall to flip. The Tories emerge with basically the same amount of seats as they went in with and, without the spectre of a second general election, Jeremy Corbyn is more amenable to the so-called McDonnell plan. He quits, and Johnny Mac is leading the opposition within six months.
Johnson has less wiggle room than May and a lot more enemies. His freewheeling and bluster doesn’t get him very far and, unlike OTL 2019, the national patience with Brexit hasn’t snapped yet so he doesn’t have many opportunities to flip the table. As with his leadership post-Partygate, a crack in the dam legitimates a raft of pre-existing doubts about his style and effectiveness in the top job. A spate of Cabinet resignations (the killing blow by Deputy Prime Minister Michael Gove, who wishes he’d never signed off on the whole bloody enterprise) forces the PM out in late-2018 or early-2019, around the same time that May hit the 48 letter mark.
Theresa May has a lot going for her in the 2018 or 2019 leadership contest - she was runner-up in 2016 and, as Johnson’s Defence Secretary (rumoured OTL), she’s got sufficient distance from the Brexit mess and acclaim for her handling of the Salisbury poisonings to easily get over the line.
She enters Downing Street and indicates her intention to go down the indicative vote path as per OTL, but her heart isn’t really in it and everyone knows it. Johnson’s resignation from Parliament technically removes the Tories’ remaining majority, and that’s excuse enough. She cuts and runs (unlike 2016, mistakenly viewing a solid leadership win as a validation of her skills as a campaigner), but her request for an extension to do so rubs a lot of people up the wrong way. Attempts to rise above the Brexit debate look awfully second referendum-friendly and, as Nigel Farage barely has time to put his pants on, the Tory campaign is marked by significant infighting about Europe. It all goes tits up as her strong (but not stable) 8-point polling lead vanishes before her eyes.
Satisfyingly, Johnson’s old seat is the one to put McDonnell over the majority line.
