Cameron's Unlikely Alliance With Sadiq Khan
Personal grudges are set aside as the Prime Minister joins forces with Labour's London mayor to deliver an EU message.
Just last month David Cameron tore into Sadiq Khan for sharing a platform with an "IS supporter," yet on Monday he lauded the London Mayor as a "proud Muslim."
That's the warping effect of a tightly fought referendum campaign when political careers are in the balance.
The prime minister has observed the political calculus: he needs Labour supporters and young voters to turn out in force for the 23 June vote, and the new mayor of London speaks to both camps.
But it does give opponents of Mr Cameron - both within and outside his party - another chance to question his political sincerity.
His attacks on Mr Khan in the Commons less than a month ago were delivered with focused ferocity, leading to accusations of racism.
Today - if not linking arms - they certainly seemed at ease with each other, setting out Stronger In's "unity of purpose" - allowing the "son of a stockbroker and the son of a bus driver" to share a stage.
Mr Khan argues the issue is too important to allow personal grudges to get in the way.
So I asked him why Jeremy Corbyn couldn't be equally magnanimous and campaign with the prime minister? He refused to answer; the mayor has a chippy relationship with the Labour leader after the mayoral tussle.
The pledge card launched today contains familiar bullet points set out as guarantees: of full access to the EU's single market, workers' rights protected, keeping the European Arrest Warrant, the UK maintaining its special status in Europe, and stability.
Mr Cameron tried out some other rhetorical devices, summing up Vote Leave's vision of the shape of a post-Brexit UK in a four word refrain: "We Just Don't Know," and putting a figure on the number of those brought back to UK to face justice due to the EAW (1,100).
Vote Leave says the pledge card ignores immigration and the power of the European Court of Justice over our lives: they'll be unveiling their own unlikely alliances over the next few days.