Any communications strategy devised in Downing Street also has to compete with noisy agendas elsewhere in the party.
The "truce" between the two leaders lasted just a week as Cameron declared that Miliband had "all the moral authority of the Reverend Flowers".
To date, the coalition has unforgivably weakened Britain's climate adaptation plans.
Miliband and Clegg are ready to sign up to three debates over three weeks. They say Cameron is running scared.
The Prime Minister's persistent refusal to debate Salmond will become a running sore and an increasingly dominant aspect of the campaign.
The PM's warning that means-testing pensioner benefits would raise only "a very small amount of money" was the most notable moment in a sombre session.
The PM's loose talk on tax has distracted from his popular pledge to maintain the triple lock on the state pension.
The Prime Minister needs to reverse the foolish decisions his government has taken on flood defences.
Both men are failing to articulate a vision that says more about what kind of country Britain should become than about what it has been.