Think of Mark Latham's overly aggressive handshake with John Howard in 2004 or Liberal leader Peter Debnam's pledge to cut 30,000 public servants before the 2007 state poll.

The clumsy attempted intervention by Mike Baird's office in a report issued by its privatisation adviser UBS may well prove to be one of these.

Sure, it might not be as spectacular as those other election moments, which proved politically fatal.

But it's the first real hit to Baird's reputation during the campaign just days from the election. For the NSW Liberals that's cause for serious concern.

On Wednesday Baird admitted his staff called UBS after the report by its leading energy and infrastructure analyst concluded his plan to partially privatise the NSW electricity businesses would be "bad for the budget".

The report estimated the loss of dividends and other equivalent payments would exceed the value of the cash up front from the sale price within 18 years. In other words after 18 years, taxpayers start making a loss.

It also, embarrassingly, said the privatisation would reap $2 billion less than the $13 billion Baird has been counting on to reach his magic $20 billion for infrastructure provision.

After the call from Baird's office the report was reissued with the "bad for the budget" line removed and extra information about the economic stimulus to NSW the 99 year lease would provide.

The Premier and the bank – which is set for a multimillion dollar fees payday if the transaction proceeds after the election – have insisted the call made no difference as the bank was already rewriting the report.

And they say they had a good reason for the call: their view was the researcher failed to take into account the stimulus effect that the $20 billion infrastructure program would have on the NSW economy.

So why should the intervention reflect badly on Baird? Well, mainly because of perceptions.

It gives the impression the Premier was trying to use the undoubted influence of his office to suppress information available to voters prepared by an independent analyst on the impact of the government's signature policy.

Rightly or wrongly, it suggests to the outside observer that Baird is more interested in spinning the message than arguing his case.

This, of course, is precisely the criticism he is making of Labor's leader, Luke Foley, and his claims electricity prices will rise because of the privatisation and the state will lose billions of dollars a year.

Why is this a problem for the Liberals? Because in this campaign they have put just about all of their hopes in Baird's extraordinary popularity.

Even before the UBS incident there have been rumblings from inside Liberal ranks about the "messaging" in the campaign. The chief concern appears to be that the Coalition lacks a "narrative".

Rather than a disciplined and structured approach which focuses on the government's achievements and what it is already building, the overarching strategy seems to some to be: vote for us because Mike's a good bloke.

Indeed, as in most campaigns the Baird visage is plastered all over the Liberal how-to-vote material. The slogan on the campaign bus slogan is "Back Baird".

All of which is fine while the candidate remains popular and – as is the case – his opponent Foley is virtually invisible in the eyes of the voting public. But should Baird's popularity begin to wane, panic will quickly set in.

As the Visibility focus groups published by Fairfax Media this week show, Baird's popularity is what is keeping the Coalition ahead in the polls despite the unpopularity of its electricity privatisation plan which is still opposed by almost half the electorate.

The focus groups were also a reminder that Baird is often given the ultimate compliment: "he's not like a politician". This appears to be the key to why people like and perhaps even more importantly, trust him. It's his superpower.

Campaign blow-ups like the UBS controversy risk undermining that impression and sending the poisonous message that he's actually a politician after all. Just like the rest of them etc.

Once that rot starts to set in, it's very difficult to reverse.