Or the expedient.
Or sleeping with strange bedfellows.
Or whatever this is:
Mr Cameron congratulated Mr Khan on his victory in the Mayoral contest, saying: "I'm proud to be here with the mayor of London - with the Labour mayor of London - on this vital, vital issue."
He hailed the fact that "someone who is a proud Muslim, a proud Brit and a proud Londoner can become mayor of the greatest city on Earth. That says something about our country".
The prime minister said he expected many disagreements with the London Mayor but they were both part of "an incredibly broad campaign" in favour of EU membership.
Mr Cameron described himself as a "Eurosceptic" but said the ability to criticise the EU is "a cause of strength in our campaign... we're levelling with people, something the other side refuses to do".
The two men unveiled a "five point guarantee card" listing what they say voters will get if they vote to Remain on 23 June.
The card promises "full access" to the EU single market, protection of workers' rights, "a safer Britain" with co-operation with other EU states, the UK keeping its "special status" within the EU, outside the euro and the Schengen passport-free area and with an opt-out from the EU's aim of "ever-closer union" and "stability".
During London's Mayoral election race, Mr Cameron repeatedly attacked Mr Khan for having a history of sharing platforms with extremists, which Mr Khan rejected.
At Prime Minister's Question Time in the Commons some Labour MPs denounced Mr Cameron as a racist when he attacked Mr Khan's judgment.Now, of course, all is forgiven in the service of a larger cause (much in the same way that Marco Rubio has "forgiven" his former opponent, the nasty, brutish and short-tempered Donald Trump).
|David Cameron: desperate, feckless and terrified. Donald Trump: nasty, brutish and short-tempered.