May's self-styled 'strong and stable' persona had morphed into something, frankly, 'a bit weird'. We know what happened next.
So far in this campaign, we have not (yet) seen anything like such a dramatic shift, but all eyes remain on the leaders.
Leader popularity remains the best predictor of electoral outcome: at no point since 1979 has the least popular gone on to win.
In an increasingly presidential-style contest, the leader is the personification of the party he or she represents.
When politics-weary voters are noticing little of the campaign, the leader becomes a shorthand for everything.
Going into the 2017 campaign, Theresa May had most to lose.
She was expected to win, and win big, while Jeremy Corbyn only had to exceed the very low bar set for him to claim a victory of sorts.
Similarly in 2019, Boris Johnson, while less admired than many of his predecessors in Number 10, is the only current political leader to enjoy net positive approval scores.
He beats Corbyn on a range of issues including best PM, best representative of Britain abroad, best at managing the economy, best at managing Brexit and, more recently, best at running that most Labour of institutions: the NHS.
Digging beneath these numbers in a focus group of undecided voters last week it was clear how much better voters feel they know the two main protagonists than they did in 2017.
Views of Johnson divide by referendum vote rather than traditional party lines.
Leavers see him as powerful, energetic and focused: a lion, a bear or an eagle. "He goes straight for it, and he's focused on the result that he wants."
Weasel, fox, snake or sloth
By contrast, remainers see him as untrustworthy (a weasel, or fox). Corbyn is untrustworthy too (a snake) but also lazy (a sloth) – but several point out that he gets a tougher press than Johnson. "I think he's like a camel. He's a decent person with liberal views but has such a load on his back – a heavy load to bear."
Which brings us to Tuesday night's debate.
In 2017, a Hansard Society poll found voters claimed the debates influenced their decision more than anything else.
In this week's head-to-head, Johnson was predicted by voters to be twice as likely to win.
In a frustratingly staccato format neither performance stood out, although Corbyn seemed more composed; Johnson more chaotic.
A snap poll by YouGov declared the battle an overall draw, with Corbyn ahead on being 'in touch' while Johnson led on being 'Prime Ministerial'.
Asked separately about each leader, 59 per cent said Johnson did well, 67 per cent felt Corbyn did.
This was far from the decisive victory that Johnson expected and Corbyn needed.
With three weeks to go – and given that 17 per cent (23 per cent of women) still have to make up their minds – either outcome still seems possible.
Deborah Mattinson is a former pollster for Gordon Brown and the founding partner of BritainThinks
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