Analysis: National MPs who tried and failed to take down Christopher Luxon on Wednesday should be embarrassed and ashamed.

After plotting, leaking, and destabilising the party enough to pressure the National Party leader into calling an emergency in-person caucus meeting, the agitators could not get the job done.

In the process they've left Luxon wounded and limping his way to the election with a caucus, which as far as the public is concerned, is more interested in itself and its own ambitions than the cost-of-living crisis much of the country is enduring.

Luxon has identified one of the detractors and made him the fall guy. After fleeing Parliament for Auckland, the prime minister sent out a statement saying Defence Minister Chris Penk was to blame for the destabilisation after launching a leadership challenge this week, resulting in the confidence vote.

"This makes his role untenable and as such I have removed his portfolios," Luxon said.

By 8pm Penk had given up any pretense he could stay on in the party and announced he wouldn't seek re-election in November in his safe seat of Kaipara ki Mahurangi - a seat once held by Sir John Key.

It's a bold call to punish his opponents, and a bit of a farce when he's only gone after one of what is clearly a group of disgruntled MPs.

But he could hardly demote senior MPs like Erica Stanford and Chris Bishop - two of his best operators - who were clearly being lined up as the true leadership contenders.

So for now Luxon has to leave it at one and hope that that has sent a strong enough message to the rest of the anti-Luxon brigade to keep their grievances to themselves until the election has run its course.

The instigators of a second round of confidence vote chaos have now had their chance and must accept the mess the party is now left with until the election.

Luxon looked like he had been through 12 rounds in the ring when he fronted the media after a three hour caucus meeting.

He spoke for a total of 75 seconds where he confirmed he had won a confidence vote, and had the full confidence of a caucus that was "united and determined to win this election".

In a complete repeat of his April confidence vote, he made his remarks following the meeting in the Banquet Hall - the least prime ministerial room in Parliament - and took no questions from the waiting reporters.

Unlike in April he didn't label the whole saga a "media soap opera" or blame reporters for the speculation and rumour. Instead he trotted out National's tired promise to "fix the basics and build the future".

Yet National has failed in the basics of what is a functioning caucus - being unified behind its leader. Likewise it hasn't looked like a party with any idea who might be its leader tomorrow, let alone in the future.

Within hours of the short and sombre press conference ending, the party was trying to return to some sense of normality with a media advisory from Bishop about an announcement on Thursday morning and an education press release from Stanford.

Meanwhile, Luxon was straight back to Auckland to prepare for the arrival of the Vietnamese president, who up until 1pm on Wednesday would have been wondering who he would be meeting the next day.