What National has not bargained on is the current level of turmoil possibly draining off more political capital than it can really afford.
In the space of barely five months, the Key-led National minority Government has gone from bullet-proof to bullet-riddled.
Since late January, when the political year started, National has stumbled from blunder to mini-crisis to embarrassment.
Almost without fail - two exceptions being welfare and (so far) local government reform - National has tended to end up on the losing side of the argument.
Even when the Government managed to set the political agenda - the case with its round of pre-Budget spending announcements - it all ended disastrously in the row over class sizes.
The problems have ranged from the banal - Gerry Brownlee's one-man war against Finland which required an apology from Key to Helsinki - to calamities like the resignation of Nick Smith.
There have been the near-scandals and consequent demands for inquiries, which National has refused to satisfy - another bad look.
Some of the distractions and sideshows will have already been forgotten. But some will stick long in the public's consciousness. These include the arguments over asset sales and raising the age of entitlement for national superannuation. On both, National is very much in the minority.
The slow train wreck that is the current National government has received criticism from both left and right alike, and the polls are only just starting to reflect that. In fact no poll has yet shown the publics response to the back-down over the class size debacle, so there's likely to be some pretty bad news for the rightwing in the next round of polling.
The problem is that John Key doesn't really care, because as long as he gets to sell our assets, he's done his job... and I'm not talking about his job as Prime Minister either.