I noted yesterday that Owen Smith has already conceded defeat on the ideological battleground in Labour’s leadership contest. He has opted instead to mimic Corbynism and fight the campaign almost entirely on questions of competence.

Given that focus, it’s unfortunate that competence appears to be one of Smith’s weaker spots. In today’s BBC hustings he committed a jaw-dropping error, saying that we should include ISIS in talks on the future of Syria.

Corbyn, by contrast, simply said: “They are not going to be round the table. No.”

That’s right – the supposedly “moderate” challenger for the Labour leadership has performed the impressive feat of making Jeremy Corbyn look like the more sensible option when it comes to terrorists.

Given Corbyn’s past attitudes to Hamas, Hezbollah and the IRA, it’s probably only temporary (indeed he has in the past argued for back-channel talks with ISIS) but for a day at least he looks like the slightly less loony option of the two.

Smith’s post-debate clarification didn’t help much, either. Apparently his spokesman then tried to spin that: “Owen is clear that there should be absolutely no negotiation with Daesh, or any terrorist group, until they renounce violence”.

For a start, no, he was not “clear” on that point. His only caveat in the debate was that “at the moment, [ISIS] are clearly not interested in negotiating”. I would submit that there are rather more serious issues with the group than their willingness to haggle over the future of their murderous “state”.

If Smith does indeed believe there should be no talks with ISIS until they “renounce violence” (something he neglected to say on air), what does that really mean? It’s not clear that it means anything in practice. The whole reason that ISIS are an issue is that they are inherently violent – there’s no vegan, Buddhist, Coldplay-listening ISIS 2.0 out there to talk to instead. That’s kind of the problem.

If you’re pitching yourself as a competence candidate, it’s probably best not to put yourself in a situation in which the Corbyn campaign can accurately describe your views on ISIS as “hasty and ill-considered”.

All in all, it was a disaster. Ironically, the comment won’t have appalled the Corbynite bulk of the Labour membership in the same way as it would appal millions of traditional Labour voters. But the clumsiness of the whole episode will raise serious doubts among some of Smith’s key backers. They picked him over Eagle on the basis that he would be better at showing up Corbyn’s lack of political skill. They may now be regretting it.