Nothing this week had a hope of upstaging the fall and fall of Chris Carter, which had the public transfixed by the MP's sheer bloodymindedness and the root cause of his self-destruction.

As a Shakespearean-like tragedy, Carter's mixture of anguish and antagonism running headlong into Phil Goff's ruthlessness overshadowed everything.

Not even Monday's far more momentous matter of National and the Maori Party finally reaching agreement on how to deal with the vexed question of ownership of the foreshore and seabed could compete.

But the contrast between Labour's turmoil after Goff's demotion of Carter and subsequent decision to send the MP home on stress leave and National's success in healing what the Prime Minister calls a "weeping sore" was testimony to the vast gulf in performance between the two parties and a brutal indication of the size of the mountain Labour has to climb between now and next year's election.

While Goff was nailing Carter to the cross, John Key was nailing down a deal with the Maori Party which is a huge stride toward National retaining the Government benches after the 2011 election.

The agreement does not oblige the Maori Party to again come in behind National once the votes have been counted on election night. But it most surely boosts the likelihood of that happening.

That was apparent from the personal dynamics between politicians from both parties at Monday's announcement.

Clearly, negotiations over the fine print were tough and taxing.

Having reached agreement on such a complex and divisive issue, however, the deal will strengthen bonds between the parties and act as a buffer against any events capable of damaging the relationship.

To look at it in another way, failure to reach agreement on such a fundamental component of the support agreement between National and the Maori Party would have been a huge irritant and would have left the Maori Party vulnerable to charges of failing to deliver.

Labour argues the deal is not vastly different from the Foreshore and Seabed Act it passed and which the Maori Party so vehemently opposed.

Labour says it is also barely distinguishable from the proposal mooted in the discussion document released by Attorney-General Chris Finlayson in April. So what has changed?

Labour might be oversimplifying things. National is now light years away from where it stood when the act was passed in 2004.

It has ultimately had to accept Maori effectively having "ownership" of parts of the foreshore and seabed, with the property rights which come from ownership to commercially exploit those areas.

The caveat is that the "ownership" is not freehold title, thus forbidding sale of any part of the foreshore and seabed. But the Maori Party can live with that because it will still be an actual property title.

National has also tried to mask what will be de facto ownership by Maori by stressing the foreshore and seabed will be designated as "open space" which will be incapable of being owned in a fee-simple sense like a house or private land.

The Maori Party would have preferred such artifice - designed to appease Pakeha but essentially meaningless - was absent. But if the concept of "open space" spares National's blushes, then so be it.

These concessions make a mockery of claims that the Maori Party has sold out, especially when placed alongside other elements of the package such as the provision of new High Court arrangements for seeking customary title and the ability for iwi to negotiate directly with the Crown to secure customary title.

However, National has sought to balance these concessions by setting a high bar when it comes to iwi being able to prove their right to customary title.

National is gambling that the test will be tough enough to avoid large areas of the foreshore and seabed gaining such title.

Whether that turns out to be the case will hinge on the wording of legislation enacting this week's agreement and the ways in which the High Court interprets it.

Those two unknowns make it impossible to pass final judgment on the agreement.

For now, the fact that there is agreement is more important.

It was inevitable that there would be a deal despite the Maori Party expressing doubts the week before last that it could reach one.

The wider politics deemed that there be one. With Act's shifting loyalties likely to be in even more flux National will need the continued support of Tariana Turia, Pita Sharples and company on confidence motions unless it can govern in its own right or inveigle the Greens into some kind of working-together arrangement.

If National has had to pay a premium to up its chances of retaining Maori Party support, the price was lower than it might have been.

For the Maori Party likewise had to settle the matter - and not just because the foreshore and seabed is of such fundamental significance to the party's membership.

Alongside whanau ora, the United Nations Declaration on Indigenous Rights and stiffer taxes on tobacco, enhancing iwi rights to seek and secure customary title is an even bigger trophy to wave in front of Maori voters.

Small parties operating in governing arrangements need as many prizes as possible - and they need to show they wielded some power by forcing those concessions.

There is no question that Turia would have driven a hard bargain. But she was also realistic enough to accept that National had only so much room to move.

Her and other Maori Party MPs' pragmatism is measured by Hone Harawira's splendid isolation as the purist's voice attacking the deal as inadequate as far as Maori are concerned.

But Harawira's more radical stance raises another question.

Once the foreshore and seabed has finally been put to bed, the party's raison d'etre will have to change.

Does it shift leftwards and compete with Labour, taking stances which make it harder to deal with National?

Or does it shift rightwards to be an alternative to Labour and find itself in territory where Maori are few and far between?

Those questions probably won't be answered before next year's election - and National will maintain a give-and-take approach to Maori Party demands to avoid them being asked.

The other question is whether Labour will carry on being so hostile to the Maori Party now that Shane Jones, one of the leading protagonists, has been sidelined.

That strategy has proved to be largely counter-productive - succeeding only in driving the Maori Party closer to National.

As this week's deal shows, Key has no compunction about making compromises to keep it there.