The value of trust to both politicians and businesses cannot be overstated.
With it comes a licence to operate and the freedom to make controversial decisions. Without it, every judgement is questioned, every decision subject to withering scrutiny.
The details of Blair's credibility gap on Iraq are unambiguous. An NOP poll this week claimed that 60 per cent of the population believed he had lied over the threat posed by Iraq. Two-fifths said he should resign.
And yet, the sort of trust needed to govern effectively is not one-dimensional.
It is perfectly conceivable to trust someone on one issue, but not on another - to allow some latitude on public services, say, while condemning his alleged deceit on Iraq.
The Labour Party, of course, trusts Blair on neither. But then, as was underlined anew by his speech in Bournemouth, the leader's cool relations with the party have always been offset by the fact that he commands popularity in the wider electorate. Polls this week suggesting a continuing Labour lead over the Tories and the Liberal Democrats can only confirm that view.
So those advising the Prime Minister clearly feel all is not lost on issues outside the Iraq quagmire. The launch of what Blair called the largest policy consultation exercise in British history will have lobbyists rubbing their hands in anticipation. For a leader beset by allegations of arrogance and ignoring advice, it was also a PR masterstroke.