The Coalition had a prima facie case against Wayne Swan regarding the attention he, his office and Treasury gave to John Grant's finance request. There was enough there for a solid week of parliamentary jousting and maximum potential to inflict damage.

But Turnbull went for the ultimate prize, the Prime Minister, Kevin Rudd.

An email that linked Rudd's office to representations made on behalf of Grant was a smoking gun indeed, if only it were real.

It would show Rudd had misled Parliament, egregiously. A sackable offence.

Yesterday's revelation (June 22) that it was a fake opened a great big hole in the fence, and the Government piled on through.

By the day's end the Coalition benches were a picture of misery. Faces told of an opportunity lost.

Turnbull and Joe Hockey went through the motions of questioning Swan over the treatment of finance requests by car dealers, but there was no passion.

They had overreached and lost the day. They had based their big push on a bent email.

Ironically, when Turnbull was "bullying" Rudd's economic adviser Andrew Charlton at the mid-winter ball, presumably over the email, Liberals from South Australia were outside on their phones.

They were occupied with the imminent dumping of the state's Opposition leader, Martin Hamilton Smith, who fell from grace after trying to stitch up the Premier, Mike Rann, with what turned out to be a sheaf of fake emails.

In retrospect, Turnbull et al should have sniffed trouble given the vehemence of Rudd's parliamentary denials of any wrongdoing.

Rudd may be a relative political greenhorn; the ute shows that. But he is no idiot. After checking thoroughly, he was emphatic in Parliament about neither he nor his office ever passing on a request on behalf of Grant.

Yet the Opposition thought it had them both on toast.

"The Prime Minister and the Treasurer have used their offices and taxpayers' resources to seek advantage for one of their mates, and then lied about it to Parliament," Turnbull thundered on Friday night.

By yesterday afternoon the cigar had exploded, and Turnbull said: "The email was not created or composed, nor was the text provided to the News Limited journalist Steve Lewis by anybody in the Opposition."

Traps for young players.

This opinion piece was first published in The Sydney Morning Herald.