COMMENT: Having your leadership locked into a single issue is never a good idea.
John Key did it, promised that the age of the pension would never rise above 65 while he was the Prime Minister.
He had his Government stick to it even though the pressure was growing to raise the age.
That all changed when the pragmatic Bill English increased the age on taking over the Beehive's ninth floor office, but hedging his bets with the electorate by having the higher age starting to kick in when they're all in retirement homes.
Now Jacinda Ardern's painted herself into a corner, and like Key, it's not an insignificant economic one.