National's playing of the race card has produced the expected response from the Maori Party: they have now ruled out any post-election deal which would see National take power. Declaring that abolishing the Maori seats is a bottom line is also likely to cause trouble with New Zealand First, who have ruled out such an extreme measure. The upshot is that National is rapidly running out of coalition options. By offending the Maori Party and deliberately placing a barrier in the road to cooperation with Winston, they have narrowed their potential support bloc down to ACT (who won't be in Parliament) and United Future (who are polling between 1 and 2 % and so will get at most 3 MPs). Which means they have effectively ruled themselves out of any chance at power.
I know it's been said before, but I'll say it again: National doesn't understand MMP. They think that they can win an election alone, or that other parties will just obediently fall into line because of their "natural right to rule". But it just doesn't work like that anymore - and hasn't since 1996. I know they're a conservative party, but you'd think National would have woken up to this, having had nine years to get used to the fact. But instead, they seem to have spent those nine years living in denial, hoping desperately that this messy experiment with democracy will go away, and that we'll all snap out of our "silly infatuation" with representative government. But I don't think that's going to happen - which means National will stay in the political wilderness until it finally begins to understand the fact that it needs friends and must compromise on its agenda, rather than enjoying automatic support simply because they're old and bald.