There is danger in commenting on what is clearly a developing political story from afar but for what it is worth here goes.
MMP is the bastard political system inflicted on Germany by the allies post WW2 designed to make it virtually impossible for no one Party to govern alone. Right now NZ is stuck with it and forget the stellar polling enjoyed by National. National needs political allies if it is to govern in the medium to long term.
Labour has the Greens and NZ First as natural allies. The Maori Party is undergoing its own inner turmoil and cannot be counted on as a natural ally of the Centre Right. It is unlikely the Dunne Party will survive the election and even if it were to make it over the line it would remain a one seat wonder with its vote available for purchase by the highest bidder.
So all that National is left with is ACT. I am not privy to our internal polling but the advice I have from several sources is that right now ACT is mired in the 1-2% margin of error stuff. Their Leader is not polling well in Epsom, particularly among female voters, and without Epsom ACT is out of Parliament.
It has to be remembered too that in both 2006 (under Brash) and in 2009 (under Key) National sent a deliberate nudge nudge wink wink to its supporters to support ACT with their electorate vote.
A large part of politics is about perception and right now the perception is that ACT is damaged goods.
Enter Don Brash. From where I sit I have to say my assessment is that if he were to go with his own Right Wing Party (as he has threatened to do) he would bury ACT. The problem for ACT, in deeding him the leadership, is that while Brash sits squarely with the Douglas/Richardson economic faction, he is a social conservative. It is a moot point how that would play out on their declared liberal/libertarian tradition.
For all his good points Brash remains politically naive. A case in point is his championing of John Banks for Epsom. JB is a political Peter Pan and yesterdays man who managed to wrest defeat from the jaws of victory. Is he to be the bright new face of ACT going forward and is Brash saying he would prefer Banks over Boscowan as an ACT nominee for cabinet? (because you can be as sure a god made little apples, Banks wouldn't be going to parliament to sit on the back benches.
So there are risks for ACT and while Brash would certainly bleed off right wing voters from National he would also change brand ACT and move it way from its liberal tradition.
But to end where I started. National needs allies and right now I doubt whether ACT as it currently stands, and certainly in the face of a Brash lead alternative party, will be in parliament post November. So on balance, and unlike my good friend Adolf, the Veteran supports the bid by the Brashites to take-over ACT risks et al.