It would be commendable for the Conservative leader to insist his party offers a positive vision of his 'big society' agenda - it would fit with the political strategy of 'reassurance' and countering fears of a Tory government which informed his approach to Thursday's debate.
But many in his party want a much tougher aggressive response towards both the Liberal Democrats and Gordon Brown's Labour government, against which the Conservatives have consistently been fighting a highly negative campaign for months.
Cameron has previously admitted he had broken his promise to "end Punch and Judy politics", which he had made a central point of his wish to do politics differently on becoming party leader:
“I will absolutely hold up my hands and say this is a promise I have not been able to deliver,” he told the Today programme.
I take a robust approach. I don’t make any apology for that,” he said.
“The quieter tone I’d hoped we might be able to have, the better discussion of politics at Prime Minister’s Questions, doesn’t work.”
The question of what the Tories will do this weekend reflects one of the core unresolved strategic tensions about the content, message and tone of the Conservative campaign - with his guru Steve Hilton wanting a thematic "hope" campaign focused on a positive vision, and his communications director Andy Coulson believing in a much more aggressive and punchy "pub ready" assault against political opponents.
This is decision time.
My guess is that, with the pressure very much on the Tory camp, Coulson will prevail - and that the Conservatives will attack the LibDems hard over immigration, defence, crime and tax.
With the leader having promised the opposite, perhaps we can expect a more upbeat and positive Tory message this weekend after all.