This is one role Arnold Schwarzenegger most definitely won't be auditioning for. Neither, for that matter, could Wayne Mapp have ever imagined he would be cast as National's new "political correctness eradicator" when he gave a rather dry speech on the subject four months ago.

The bizarre title sounds like the Terminator-meets-local-pest-control-officer.

It is difficult to picture the somewhat pompous-sounding but deep-thinking and diligent North Shore MP as a caped crusader exterminating politically correct outpourings from the bureaucracy and academia.

It is somewhat easier to imagine the collective sighs of Don Brash's advisers when National's leader came up with the idea as part of the post-election reshuffle of his shadow Cabinet.

Labour's Michael Cullen was typically acid in slamming the concept as "chillingly fascist-sounding". But the Eradicator is more Monty Python than Nazi Germany.

For all the ridicule, however, the chattering classes are quick to forget just how much National benefited at the election by exploiting the latent unhappiness with so-called politically correct policies.

The downside for National lurks in the Eradicator being a turnoff for the party's liberals, a fair chunk of whom reside in big city electorates like Mapp's.

No surprise then that he is taking a deep breath. He intends giving the idea some "intellectual rigour" before working out his modus operandi.

The more immediate impact of the Eradicator was to distract attention from the marked shift in strategic thinking contained in Wednesday's reshuffle.

The revamp dispenses with the usual practice that portfolios be allocated with some regard to those best qualified to do the job in Government. The prime driver now is performance in Opposition - who is likely to make the biggest hits on Labour.

The reshuffle puts the National caucus heavily into attack mode - and with good reason. The more seasoned hands in the party's caucus remember how Labour chipped away at National remorselessly during the latter's third term in the late 1990s.

Helen Clark successfully portrayed National as a tired Government fatally afflicted by a "culture of sleaze" which had it looking after only its mates and selling its soul to stay in power.

National sees history repeating itself - but to its benefit this time.

Labour now has constantly to combat the third-term blues. Moreover, the mercenary nature of Labour's deal with NZ First and Winston Peters' acceptance of the "baubles of office" have badly tainted the new Government before it has barely started.

Brash must ram home the advantage over coming months - and not just for the sake of his leadership, the future of which will have to be settled one way or the other in the latter half of next year.

While National did splendidly in capturing 39 per cent of the vote in September's poll, the party is acutely conscious that its failure to strip votes off Labour cost it any realistic chance of forming the Government.

National needs to hold or better its vote in 2008. But it must also push Labour's share down to 35 per cent or thereabouts to leave the minor parties no option but to go with National.

National is also conscious that Labour will copy some of its more enticing policies. That has already begun with Cullen forming a ministerial "razor gang" to scrutinise Government spending. And it is a certainty that Labour will cut taxes one way or the other.

All the above makes it vital that National's attack mechanisms are functioning effectively.

Brash wants a much sharper, more aggressive performance from his colleagues - and himself. The reshuffle of caucus responsibilities is the first step.

Brash has listened to the call coming from across his caucus to abolish Murray McCully's formal role as the leader's primary adviser. McCully could see the writing on the wall and volunteered to relinquish the role anyway.

That has removed a major irritant in caucus relations. Those complaining about McCully's influence argue that the front-bench should now be more cohesive - as long as Brash actually takes wider counsel.

Brash has bitten the bullet in demoting Lockwood Smith, John Carter and Paul Hutchison, the latter bluntly told he is not "best suited" to the attack role of Opposition.

Other MPs have been plucked out of their comfort zones and thrust into more challenging portfolios in order to "take the attack to Labour".

Four frontline MPs with new jobs - Tony Ryall, Nick Smith, Simon Power and McCully - are up against new ministers. They thus start on equal footing with their adversaries. It will be obvious who is making an impact and who isn't.

The same applies to four other senior MPs - Gerry Brownlee, Bill English, Katherine Rich and Judith Collins - who retain their former roles but who are also up against new ministers.

Brash has been true to his market principles. The reshuffle is designed to create a culture of competition on National's front bench.

Previously, there was a tendency for everyone to sit back and bask in the success of a colleague - rather than trying to match it. The large intake of new MPs now means poor performers can no longer relax.

Two of those new MPs, Tim Groser and Chris Finlayson, have already soared up the caucus rankings over the heads of long-serving MPs. If that is not enough to focus minds, Brash intends reviewing performances in a year's time.

If all this competition lifts National's game, Brash will be the winner.

One question lingers, however. Will running a successful Opposition be sufficient to dispel caucus worries about retaining a leader who will celebrate his 68th birthday during the next election campaign?

If there is to be a change, the preference is it be a managed one. No one wants things to get messy. But if the mood determines Brash has to go, then he will have to go.

Brash has declared he will stay on and fight the next election as leader. But that statement was necessary to stop reporters asking him when he plans to step down.

The reshuffle offers no clues as to his private thinking. But this was not a "job for the boys" exercise. Some of his allies have suffered. No one can argue that Brash has put his future ahead of the party's.

His triumph at the ballot box gave him a mandate to ring the changes. He hasn't wasted it. Regardless of who ends up being leader, the party should be very grateful for that.