For the second time, Donald Trump has made waves in the Conservative leadership election, after approvingly sharing a tweet by Katie Hopkins, a far-right provocateur, attacking Sadiq Khan and referring to the nation’s capital as “Londonistan”.

Five of the six remaining candidates were grilled by the Parliamentary Press Gallery today, and they offered different responses. Michael Gove, Dominic Raab and Sajid Javid all condemned the US president, while Jeremy Hunt made the eyebrow-raising claim that he agreed with Trump “150 per cent”, and Rory Stewart refused to answer the question.

We don’t need to dwell overmuch on Raab, Gove and Javid’s answers. In the case of Raab, who talked about his fondness for London’s melting pot and his pride at having a capital with a Muslim mayor, it was an interesting example of the campaign that he could have, but ultimately failed to run. That would have seen him talk more about his work before politics in tackling international war criminals and his more heterodox opinions. Instead, he became the candidate of one tendency of the Conservative Party’s Brexit debate, and not even the sole or most convincing candidate of that tendency.

For Gove, it was a tantalising glimpse of the campaign he might have run had his second tilt at the leadership not been dominated by questions about cocaine. For Javid, it was the latest example of his intriguing frankness on race and racism in this contest. The Home Secretary has shown remarkable courage in ripping up and discarding the usual playbook for ethnic minority politicians. It bolsters the argument his campaign are making, which is that if Conservative MPs and activists are looking for a genuinely new type of Conservative to get them through a very different political moment, it is him they should be looking at. So far, that argument doesn’t seem to be making much headway as far as the support of actual MPs are concerned but it puts him in good shape to run again, whatever the result.

And then there’s Rory Stewart. Stewart’s appeal to Conservative MPs is twofold — the first is that he is someone who can win over Labour and Liberal Democrat supporters, and the second, which his campaign is not making itself but several MPs flirting with supporting him are making privately, is that if no-one can stop Boris Johnson, they might as well go out talking about what they believe in.

That appeal could yet see Stewart make the final round of voting against Johnson. But if he wants to get there, Stewart has to transform his candidacy from one running for the position of “no-hope candidate who makes people who don’t vote Conservative say ‘I don’t like Tories, but Rory Stewart is ok” to a serious candidate for power.

Today’s YouGov polling of Tory members, and Stewart’s indifferent performance in front of them on Saturday, shows that Stewart will never be the darling of Tory activists — but David Cameron wasn’t in 2005 either. What he did in his 2005 conference speech was demonstrate that he could win over people who had voted Labour in 1997, 2001 and 2005, something which transformed the leadership election.

If there’s a point to Rory Stewart, then it is to prove to the Conservative membership that he can do what the other candidates, and Johnson most of all, cannot. The problem for Stewart is that his campaign can’t quite decide if it is a hell for leather run to be the candidate who can win over social liberals and Remainers, or if it is a bid for greater prominence under another leader. The result is a candidacy that talks of voting to stop a no-deal Breit and then pulls back — of a campaign that talks up its ability to win over social liberals and then won’t criticise Donald Trump.

The risk for Stewart is that if he isn’t the candidate who will criticise Trump for repeating a far-right meme about Sadiq Khan, who is he the candidate for?