If David Cameron was confident that he would win the TV debates, he would have already signed up for them. That he is not even willing to begin negotiations until October is evidence that he is reserving the option to avoid them. By the same measure, Ed Miliband would not be pushing for an agreement if he did not believe that he would emerge the victor.
It is the fear that the debates would advantage one or more of his opponents that explains Cameron's hesistancy. Labour figures rightly regard them as an opportunity for Miliband to speak directly to the country, unmediated by a hostile press, and as a means of countering the Tories' financial advantage. Having performed credibly against Cameron at PMQs in his three-and-a-half years as leader of the opposition, they are confident that Miliband would surpass expectations. As the papers demonise him as the most dangerous man in Britain, voters may warm to the moderate figure who wants to freeze their energy bill and build more homes. It is Cameron, as both the Tories and Labour recognise, who has the most to lose.
The latest attempt to inject momentum into the discussions is a joint proposal by the Guardian, the Telegraph and YouTube to host an online debate. The aim is to engage young viewers for whom the internet is the main source of news and who are alienated by traditional broadcasters. It is a worthy one. But by adding a new element to the negotiations (and encouraging others to make similar proposals) it increases the possibility that Cameron will find an excuse to avoid them altogether. A Miliband source told me: "This shows why we need the talks to begin now, with 3-3-3 as our starting point."
Both Labour and the Lib Dems regard a repeat of the format used last time - three debates between three party leaders over three weeks - as their best hope of securing an agreement. Cameron's alternative proposal of a "2-3-5" format with a head-to-head debate between himself and Miliband (before the campaign proper begins), another with the addition of Nick Clegg, and another with the addition of Nigel Farage and the Greens' Natalie Bennett is regarded with suspicion as an attempt to muddy the waters. As Labour's Michael Dugher has pointed out: "It’s nonsensical for Cameron to say he wants to start the debates early, but the negotiations late."
The more parties, broadcasters and papers pile in, the greater the chance that Cameron will eventually announce with faux sincerity that "We tried really hard, we really did, but it just hasn't been possible to reach an agreement."