Doomed, kaput, done for, dead and buried: Act has been written off more times than your typical boy-racer's standard low-slung two-litre turbocharged pride and joy.

Even allowing for yesterday's belated decision by David Garrett to quit Act before he got the boot from Rodney Hide, the wreckage now masquerading as a political party is beyond restoration - certainly while Hide remains at the wheel and just as surely were someone else in the current caucus to take his place.

Garrett's keeping secret his 2002 assault conviction from the judge handling his 2005 identity theft case provided a last-minute reason for Hide to get rid of the caucus liability.

But it left open the question of what Hide would have done without that rationale given that just two days earlier Hide had said Garrett could put the past behind him and continue as Act's law and order spokesman.

The garrotting of Garrett merely shifts the spotlight to Hide and his judgment, in particular why he appointed Garrett to the law and order post in the first place when he was fully aware of his abhorrent behaviour and why he failed to disclose that information both then and in recent days when the political heat went on Garrett to cough.

The answer lies in the deal between Act and the Sensible Sentencing Trust which parachuted Garrett into a high slot on Act's candidate list presumably in return for some kind of donation, although that has always been denied.

Whatever, Garrett may prove to be Hide's fatal error. His hold on the leadership has been under pressure for some time now. The sidelining of Heather Roy might have briefly strengthened his position but it opened the door for John Boscawen to become deputy.

Hide's complicity with Garrett makes it an even safer bet that the leadership will fall into Boscawen's lap by default.

That is because recent events have also loosened Hide's hold on his Epsom seat. National is now likely to reclaim it even though it does not necessarily want it. Without some guarantee or expectation that he can win it - and thus negate the 5 per cent threshold - Hide is surplus to requirements.

About the only thing that can save Act from extinction would be for Hide to step down and Don Brash - or someone of like stature - be installed as the party's leader outside Parliament while Boscawen retains the deputy-leadership inside.

Brash would spearhead Act's revival ideologically and organisationally. He, not Hide, would stand in Epsom. And if Hide did so as an independent, National could give Brash a free run. He would win in a landslide.

Fanciful stuff maybe. But such lateral thinking is desperately required on Act's and National's part if Act is to survive and cater for a minority on the right, thereby allowing National more latitude to hug the centre.

The alternative is to let Act die and set up a new party on the right. That may be easier. For Act, the last 12 months have been disaster after disaster. The party has veered from Hide's hypocrisy over his taking advantage of ministerial travel perks to the open factional fighting at the party's annual conference, to the dumping of Roy as deputy leader, to her exacting sweet revenge on Hide, to this week's revelations about Garrett.

Amidst the turmoil, which seems only to be intensifying, Act has lost all sense of direction, drive and purpose. The party's membership - what's left of it - has looked on in horror. Hide and Garrett have compromised Act's self-imposed high standards and principles to such a degree that voters no longer know (or care) what Act stands for beyond its MPs' self-interested scramble for parliamentary survival.

The desperate search for something, anything with populist appeal has watered down the party's original messages to the point of being meaningless.

In short, Act's once unique brand is now permanently tarnished.

Only Sir Roger Douglas has kept the faith. But even he is locked with his colleagues in the struggle for control of what is now essentially an empty shell of little or no value.

As the protagonists plunge the knife into one another, the question is, who stood to gain from leaking details of Garrett's past to embarrass Hide, the real target.

The conspiracy theorists have fingered Roy as the only person apart from Hide who would have known the details of Garrett's misdemeanours. If Roy assumed she would be relegated down Act's list, then she had nothing to lose.

Blessedly for National, Act's self-destruction has not yet caused the Government strife.

Act's MPs have nowhere else to go but to vote National. Even if they went bonkers and voted with Labour, Key would still have the Maori Party to strike down any no confidence motion.

John Key has kept his distance from Act. In his mind, Act's role is to make him look like a moderate.

Key and his deputy, Bill English, this week maintained a strict line by decreeing that Act's internal problems were Act's business alone.

In the longer term, however, National needs Act or an equivalent. National suffers from a shortage of allies with which to form a government.

Even if Act was reduced to one constituency MP, the mechanics of MMP mean that would give the centre-right one extra vote in Parliament which National could not otherwise get on the straight party vote.

The trouble now - as Phil Goff has noted - is that in asking its Epsom supporters to back Hide, National would be asking them to vote for someone they no longer want.

National has little choice but to cut its losses and find a quality candidate for what is normally a safe seat for the party.

And for Hide and his party, that spells the end.